Researcher Profile and Settings

Master

Affiliation (Master)

• Central Institute of Isotope Science

Affiliation (Master)

• Central Institute of Isotope Science

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Profile and Settings

Affiliation

• Hokkaido University, Central Institute of Isotope Science, Associate Professor

Degree

• Pharmaceutical Sciences（Kyoto University）

Profile and Settings

• Name (Japanese)

  Kuge

• Name (Kana)

  Yuji

• Name

  200901045754647029

Affiliation

• Hokkaido University, Central Institute of Isotope Science, Associate Professor

Achievement

Research Interests

• 分子イメージング   放射線   動脈硬化   腫瘍   癌   ポジトロンCT(PET)   シングルフォトンCT(SPECT)   治療   インビボイメージング   inflammation   鑑別診断   移植・再生医療   炎症   脳虚血病態   薬学   医療・福祉   放射性薬品化学・核医学・脳循環代謝学・病態分析学   Pathofunctional Bioanalysis   Nuclear Medicine   Molecular Imaging   Radiopharmaceutical   

Research Areas

• Life sciences / Radiology
• Life sciences / Pharmaceuticals - analytical and physicochemistry

Research Experience

• 2009 - Today Hokkaido University Central Institute of Isotope Science
• 2007 - 2009 北海道大学大学医学研究科 教授
• 2002 - 2007 Kyoto University Graduate School of Pharmaceutical Sciences
• 1999/04 - 2002 Hokkaido University Graduate School of Medicine

Education

•        - 1987  Kyoto University
•        - 1985  Kyoto University  Faculty of Pharmaceutical Sciences

Committee Memberships

• 2023/05 - Today   The Society of Radiopharmaceutical Science   President
• 2001/10 - Today   The Japanese Society of Nuclear Medicine   Councilor   The Japanese Society of Nuclear Medicine

Awards

• 2022/10 日本アイソトープ協会 放射線安全取扱部会表彰 功労賞
   

  受賞者: 久下裕司
• 2002 第40回 日本核医学会賞
   

  受賞者: 久下裕司

Published Papers

• Attenuated polyethylene glycol immunogenicity and overcoming accelerated blood clearance of a fully PEGylated dendrimer

  Chie Kojima, Junjie Yao, Kohei Nakajima, Motofumi Suzuki, Ayako Tsujimoto, Yuji Kuge, Mikako Ogawa, Akikazu Matsumoto

  International Journal of Pharmaceutics 659 124193 - 124193 0378-5173 2024/06 [Refereed]
  
• Feasibility study of multimodal imaging for redox status and glucose metabolism in tumor.

  Kazuhiro Kato, Hironobu Yasui, Hideo Sato-Akaba, Miho C Emoto, Hirotada G Fujii, Maciej M Kmiec, Periannan Kuppusamy, Yuki Mizuno, Yuji Kuge, Masaki Nagane, Tadashi Yamashita, Osamu Inanami

  Free radical biology & medicine 2024/04/02 [Refereed]
   

  Understanding the tumor redox status is important for efficient cancer treatment. Here, we noninvasively detected changes in the redox environment of tumors before and after cancer treatment in the same individuals using a novel compact and portable electron paramagnetic resonance imaging (EPRI) device and compared the results with glycolytic information obtained through autoradiography using 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG). Human colon cancer HCT116 xenografts were used in the mice. We used 3-carbamoyl-PROXYL (3CP) as a paramagnetic and redox status probe for the EPRI of tumors. The first EPRI was followed by the intraperitoneal administration of buthionine sulfoximine (BSO), an inhibitor of glutathione synthesis, or X-ray irradiation of the tumor. A second EPRI was performed on the following day. Autoradiography was performed after the second EPRI. After imaging, the tumor sections were evaluated by histological analysis and the amount of reducing substances in the tumor was measured. BSO treatment and X-ray irradiation significantly decreased the rate of 3CP reduction in tumors. Redox maps of tumors obtained from EPRI can be compared with tissue sections of approximately the same cross section. BSO treatment reduced glutathione levels in tumors, whereas X-ray irradiation did not alter the levels of any of the reducing substances. Comparison of the redox map with the autoradiography of [18F]FDG revealed that regions with high reducing power in the tumor were active in glucose metabolism; however, this correlation disappeared after X-ray irradiation. These results suggest that the novel compact and portable EPRI device is suitable for multimodal imaging, which can be used to study tumor redox status and therapeutic efficacy in cancer, and for combined analysis with other imaging modalities.
• Application of copper (I) selective ligands for PET imaging of reactive oxygen species through metabolic trapping

  Tetsuro Tada, Yuki Mizuno, Yuki Shibata, Hironobu Yasui, Yuji Kuge

  Nuclear Medicine and Biology 108914 - 108914 0969-8051 2024/04 [Refereed]
  
• Intravenous Administration of Mesenchymal Stem Cell-Derived Exosome Alleviates Spinal Cord Injury by Regulating Neutrophil Extracellular Trap Formation through Exosomal miR-125a-3p.

  Yutaka Morishima, Masahito Kawabori, Kazuyoshi Yamazaki, Soichiro Takamiya, Sho Yamaguchi, Yo Nakahara, Hajime Senjo, Daigo Hashimoto, Sakiko Masuda, Yoichiro Fujioka, Yusuke Ohba, Yuki Mizuno, Yuji Kuge, Miki Fujimura

  International journal of molecular sciences 25 (4) 2024/02/18 [Refereed]
   

  Spinal cord injury (SCI) leads to devastating sequelae, demanding effective treatments. Recent advancements have unveiled the role of neutrophil extracellular traps (NETs) produced by infiltrated neutrophils in exacerbating secondary inflammation after SCI, making it a potential target for treatment intervention. Previous research has established that intravenous administration of stem cell-derived exosomes can mitigate injuries. While stem cell-derived exosomes have demonstrated the ability to modulate microglial reactions and enhance blood-brain barrier integrity, their impact on neutrophil deactivation, especially in the context of NETs, remains poorly understood. This study aims to investigate the effects of intravenous administration of MSC-derived exosomes, with a specific focus on NET formation, and to elucidate the associated molecular mechanisms. Exosomes were isolated from the cell supernatants of amnion-derived mesenchymal stem cells using the ultracentrifugation method. Spinal cord injuries were induced in Sprague-Dawley rats (9 weeks old) using a clip injury model, and 100 μg of exosomes in 1 mL of PBS or PBS alone were intravenously administered 24 h post-injury. Motor function was assessed serially for up to 28 days following the injury. On Day 3 and Day 28, spinal cord specimens were analyzed to evaluate the extent of injury and the formation of NETs. Flow cytometry was employed to examine the formation of circulating neutrophil NETs. Exogenous miRNA was electroporated into neutrophil to evaluate the effect of inflammatory NET formation. Finally, the biodistribution of exosomes was assessed using 64Cu-labeled exosomes in animal positron emission tomography (PET). Rats treated with exosomes exhibited a substantial improvement in motor function recovery and a reduction in injury size. Notably, there was a significant decrease in neutrophil infiltration and NET formation within the spinal cord, as well as a reduction in neutrophils forming NETs in the circulation. In vitro investigations indicated that exosomes accumulated in the vicinity of the nuclei of activated neutrophils, and neutrophils electroporated with the miR-125a-3p mimic exhibited a significantly diminished NET formation, while miR-125a-3p inhibitor reversed the effect. PET studies revealed that, although the majority of the transplanted exosomes were sequestered in the liver and spleen, a notably high quantity of exosomes was detected in the damaged spinal cord when compared to normal rats. MSC-derived exosomes play a pivotal role in alleviating spinal cord injury, in part through the deactivation of NET formation via miR-125a-3p.
• In vivo imaging of acute physiological responses after treatment of cancer with near-infrared photoimmunotherapy

  Kohei Nakajima, Akiyo Sugikawa, Hironobu Yasui, Kei Higashikawa, Chie Suzuki, Takahiro Natsume, Motofumi Suzuki, Hideo Takakura, Mayu Tomita, Sachi Takahashi, Kenji Hirata, Yasuhiro Magata, Yuji Kuge, Mikako Ogawa

  Molecular Imaging and Biology 1536-1632 2023/05/16 [Refereed]
  
• PD1 blockade alters cell-cycle distribution and affects 3'-deoxy-3'-[18F]fluorothymidine uptake in a mouse CT26 tumor model.

  Motofumi Suzuki, Takuma Matsuda, Kohei Nakajima, Yuta Yokouchi, Yuji Kuge, Mikako Ogawa

  Annals of nuclear medicine 2022/08/15 [Refereed]
   

  OBJECTIVE: We previously reported that alterations of the tumor microenvironment (TME) by programmed death receptor-1 (PD1) blockade affected tumor glucose metabolism and tumor 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) uptake. In cancer cells, high glycolysis allows cells to sustain rapid proliferation since glycolysis is closely related to the proliferation of cancer cells. Therefore, imaging of cellular proliferation may provide more detail of TME alterations. In this study, we investigated how TME alterations by PD1 blockade affects the uptake of 3'-deoxy-3'-[18F]fluorothymidine ([18F]FLT), which is a 18F-radiolabeled thymidine derivative and is taken up by proliferating cells. METHODS: Mice inoculated with murine colon carcinoma CT26 cells were intraperitoneally administered an anti-PD1 antibody on Day 0, when the tumor volume exceeded 50 mm3, and Day 5. [18F]FLT-PET imaging was performed pre-treatment (Day 0) and post treatment (Day 7). Tumor infiltrating lymphocytes (TILs) were identified by flow cytometry. [18F]FLT accumulation and localization in tumor tissue was evaluated by autoradiography and immunohistochemistry. The cell-cycle distribution of tumors and CT26 cells exposed to cytokines (interleukin-2, interferon [INF]-γ, and tumor necrosis factor [TNF]-α) was analyzed by flow cytometry. RESULTS: PD1 blockade increased CD8+ and CD4+ T cells in tumor tissue and significantly suppressed tumor proliferation; however, tumor [18F]FLT uptake remained unchanged. Autoradiography and immunohistochemistry showed that [18F]FLT was mainly taken up by cancer cells, but not TILs. Flow cytometric analysis demonstrated that the population of cells in G2/M phase increased after PD1 blockade. Moreover, INF-γ and TNF-α significantly increased cells in G2/M phase in vitro. CONCLUSION: PD1 blockade-induced alteration of the TME increased CT26 tumor cells in the G2/M phase, which have high thymidine kinase 1 activity. Therefore, [18F]FLT is taken up by tumor cells even if tumor proliferation is suppressed. This observation may be useful for evaluating the response to immunotherapy.
• Intracerebral Transplantation of Mesenchymal Stromal Cell Compounded with Recombinant Peptide Scaffold against Chronic Intracerebral Hemorrhage Model

  Soichiro Takamiya, Masahito Kawabori, Tsukasa Kitahashi, Kentaro Nakamura, Yuki Mizuno, Hironobu Yasui, Yuji Kuge, Aki Tanimori, Yasuyuki Takamatsu, Kohei Yuyama, Hideo Shichinohe, Miki Fujimura

  Stem Cells International 2022 1 - 10 1687-966X 2022/07/31 [Refereed]
   

  Background. Due to the lack of effective therapies, stem cell transplantation is an anticipated treatment for chronic intracerebral hemorrhage (ICH), and higher cell survival and engraftment are considered to be the key for recovery. Mesenchymal stromal cells (MSCs) compounded with recombinant human collagen type I scaffolds (CellSaics) have a higher potential for cell survival and engraftment compared with solo-MSCs, and we investigated the validity of intracerebral transplantation of CellSaic in a chronic ICH model. Methods. Rat CellSaics (rCellSaics) were produced by rat bone marrow-derived MSC (rBMSCs). The secretion potential of neurotrophic factors and the cell proliferation rate were compared under oxygen-glucose deprivation (OGD) conditions. rCellSaics, rBMSCs, or saline were transplanted into the hollow cavity of a rat chronic ICH model. Functional and histological analyses were evaluated, and single-photon emission computed tomography for benzodiazepine receptors was performed to monitor sequential changes in neuronal integrity. Furthermore, human CellSaics (hCellSaics) were transplanted into a chronic ICH model in immunodeficient rats. Antibodies neutralizing brain-derived neurotrophic factor (BDNF) were used to elucidate its mode of action. Results. rCellSaics demonstrated a higher secretion potential of trophic factors and showed better cell proliferation in the OGD condition. Animals receiving rCellSaics displayed better neurological recovery, higher intracerebral BDNF, and better cell engraftment; they also showed a tendency for less brain atrophy and higher benzodiazepine receptor preservation. hCellSaics also promoted significant functional recovery, which was reversed by BDNF neutralization. Conclusion. Intracerebral transplantation of CellSaics enabled neurological recovery in a chronic ICH model and may be a good option for clinical application.
• Reduction of tumor hypoxia by anti-PD-1 therapy assessed using pimonidazole and [18F]FMISO

  Kohei Nakajima, Mitsunori Homma, Motofumi Suzuki, Yuta Yokouchi, Takuma Matsuda, Hideo Takakura, Kenji Hirata, Yuji Kuge, Mikako Ogawa

  Nuclear Medicine and Biology 108-109 85 - 92 0969-8051 2022/05 [Refereed][Not invited]
   

  INTRODUCTION: Hypoxia is common in solid tumors and creates an immunosuppressive environment that leads to resistance to immunotherapy, such as an anti-programmed death receptor-1 (PD-1) therapy. It has been suggested that anti-PD-1 therapy may reduce tumor hypoxia by remodeling the tumor vasculature; however, it is unclear how anti-PD-1 therapy reduces hypoxia over time. Therefore, we investigated the relationship between hypoxia and immune activation by anti-PD-1 therapy in murine cancer models. METHODS: Anti-PD-1 antibody was injected to CT26- and MC38-tumor-bearing mice on days 0 and 5. Tumor hypoxia was non-invasively evaluated using positron emission tomography (PET) with [18F]fluoromisonidazole ([18F]FMISO) on days 3 and 7. Histological analysis was conducted to investigate the infiltration of immune cells in [18F]FMISO-accumulated hypoxic area. In addition, the immune cell population in tumors and the percentages of cancer and immune cells under hypoxic conditions were analyzed at single-cell level using flow cytometry. RESULTS: Flow cytometric analysis of CT26 tumors on day 3 showed that anti-PD-1 therapy reduced hypoxia without inhibition of tumor growth. In addition, the infiltration of CD8+ T cells was increased in treated tumors. In contrast to CT26 tumors, the percentage of hypoxic cells in MC38 tumors did not change on days 3 and 7, and there was minimal immune activation induced by anti-PD-1 antibody. Changes in hypoxia in CT26 tumors were not detected by [18F]FMISO-PET, but autoradiogram showed that [18F]FMISO accumulated in immunosuppressed areas, where the infiltration of immune cells was relatively low. CONCLUSION: Reduction of hypoxia was induced in CT26 tumor, in which adequate immune response to anti-PD-1 therapy was exhibited, at an early time point before suppression of tumor growth. Our findings suggest that anti-PD-1 therapy can create a tumor microenvironment that facilitates immune activation by reducing hypoxia.
• Long-Term Radiation Safety Evaluation of ⁶⁸Ge/⁶⁸Ga Generator

  Sho Tomita, Kei Higashikawa, Yuki Mizuno, Tetsuroh Tada, Shusaku Tazawa, Yuji Kuge

  RADIOISOTOPES 71 (1) 1 - 8 0033-8303 2022/03/15 [Refereed][Not invited]
  
• Eribulin improves tumor oxygenation demonstrated by 18F-DiFA hypoxia imaging, leading to radio-sensitization in human cancer xenograft models

  Tomoki Bo, Hironobu Yasui, Tohru Shiga, Yuki Shibata, Masaki Fujimoto, Motofumi Suzuki, Kei Higashikawa, Naoki Miyamoto, Osamu Inanami, Yuji Kuge

  European Journal of Nuclear Medicine and Molecular Imaging 49 (3) 821 - 833 1619-7070 2022/02 [Refereed][Not invited]
  
• Influence of Linker Molecules in Hexavalent RGD Peptides on Their Multivalent Interactions with Integrin αvβ3

  Yuki Mizuno, Kohta Kimura, Satoru Onoe, Miho Shukuri, Yuji Kuge, Hiromichi Akizawa

  Journal of Medicinal Chemistry 64 (21) 16008 - 16019 0022-2623 2021/11/03 [Refereed][Not invited]
  
• Long-term Quality Control Test of a 68Ge/68Ga Generator

  Sho Tomita, Kei Higashikawa, Satoshi Ueno, Yuki Mizuno, Shusaku Tazawa, Yuji Kuge

  kaku Igaku 58 (1) 47 - 58 2021/06 [Refereed][Not invited]
  
• Determination of Brain Tumor Recurrence using 11 C‐methionine Positron Emission Tomography after Radiotherapy

  Shigeru Yamaguchi, Kenji Hirata, Michinari Okamoto, Eku Shimosegawa, Jun Hatazawa, Ryuichi Hirayama, Naoki Kagawa, Haruhiko Kishima, Noboru Oriuchi, Masazumi Fujii, Kentaro Kobayashi, Hiroyuki Kobayashi, Shunsuke Terasaka, Ken‐ichi Nishijima, Yuji Kuge, Yoichi M Ito, Hiroshi Nishihara, Nagara Tamaki, Tohru Shiga

  Cancer Science 112 (10) 4246 - 4256 1347-9032 2021/06 [Refereed][Not invited]
   

  We conducted a prospective multicenter trial to compare the usefulness of C-11-methionine (MET) and F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) for identifying tumor recurrence. Patients with clinically suspected tumor recurrence after radiotherapy underwent both C-11-MET and F-18-FDG PET. When a lesion showed a visually detected uptake of either tracer, it was surgically resected for histopathological analysis. Patients with a lesion negative to both tracers were revaluated by magnetic resonance imaging (MRI) at 3 months after the PET studies. The primary outcome measure was the sensitivity of each tracer in cases with histopathologically confirmed recurrence, as determined by the McNemar test. Sixty-one cases were enrolled, and 56 cases could be evaluated. The 38 cases where the lesions showed uptake of either C-11-MET or F-18-FDG underwent surgery; 32 of these cases were confirmed to be subject to recurrence. Eighteen cases where the lesions showed uptake of neither tracer received follow-up MRI; the lesion size increased in one of these cases. Among the cases with histologically confirmed recurrence, the sensitivities of C-11-MET PET and F-18-FDG PET were 0.97 (32/33, 95% confidence interval [CI]: 0.85-0.99) and 0.48 (16/33, 95% CI: 0.33-0.65), respectively, and the difference was statistically significant (P < .0001). The diagnostic accuracy of C-11-MET PET was significantly better than that of F-18-FDG PET (87.5% vs. 69.6%, P = .033). No examination-related adverse events were observed. The results of the study demonstrated that C-11-MET PET was superior to F-18-FDG PET for discriminating between tumor recurrence and radiation-induced necrosis.
• Inhibition of xanthine oxidase in the acute phase of myocardial infarction prevents skeletal muscle abnormalities and exercise intolerance.

  Hideo Nambu, Shingo Takada, Satoshi Maekawa, Junichi Matsumoto, Naoya Kakutani, Takaaki Furihata, Ryosuke Shirakawa, Takashi Katayama, Takayuki Nakajima, Katsuma Yamanashi, Yoshikuni Obata, Ippei Nakano, Masaya Tsuda, Akimichi Saito, Arata Fukushima, Takashi Yokota, Junko Nio-Kobayashi, Hironobu Yasui, Kei Higashikawa, Yuji Kuge, Toshihisa Anzai, Hisataka Sabe, Shintaro Kinugawa

  Cardiovascular research 117 (3) 805 - 819 2021/02/22 [Refereed][Not invited]
   

  AIMS: Exercise intolerance in patients with heart failure (HF) is partly attributed to skeletal muscle abnormalities. We have shown that reactive oxygen species (ROS) play a crucial role in skeletal muscle abnormalities, but the pathogenic mechanism remains unclear. Xanthine oxidase (XO) is reported to be an important mediator of ROS overproduction in ischemic tissue. Here we tested the hypothesis that skeletal muscle abnormalities in HF are initially caused by XO-derived ROS and are prevented by the inhibition of their production. METHODS AND RESULTS: Myocardial infarction (MI) was induced in male C57BL/6J mice, which eventually led to HF, and a sham operation was performed in control mice. The time course of XO-derived ROS production in mouse skeletal muscle post-MI was first analyzed. XO-derived ROS production was significantly increased in MI mice from days 1 to 3 postsurgery (acute phase), whereas it did not differ between the MI and sham groups from 7 to 28 days (chronic phase). Second, mice were divided into three groups: sham+vehicle (Sham+Veh), MI+vehicle (MI+Veh), and MI+febuxostat (an XO inhibitor, 5 mg/kg body weight/day; MI+Feb). Febuxostat or vehicle was administered at 1 hr and 24 hr before surgery, and once-daily on days 1-7 postsurgery. On day 28 postsurgery, exercise capacity and mitochondrial respiration in skeletal muscle fibers were significantly decreased in MI+Veh compared with Sham+Veh mice. An increase in damaged mitochondria in MI+Veh compared with Sham+Veh mice was also observed. The wet weight and cross-sectional area of slow muscle fibers (higher XO-derived ROS) was reduced via the downregulation of protein synthesis-associated mTOR-p70S6K signaling in MI+Veh compared with Sham+Veh mice. These impairments were ameliorated in MI+Feb mice, in association with a reduction of XO-derived ROS production, without affecting cardiac function. CONCLUSIONS: XO inhibition during the acute phase post-MI can prevent skeletal muscle abnormalities and exercise intolerance in mice with HF. A TRANSLATIONAL PERSPECTIVE: We clearly demonstrated that febuxostat, an inhibitor of xanthine oxidase (XO), prevents exercise intolerance and skeletal muscle abnormalities (mitochondrial dysfunction and atrophy) via the suppression of XO-derived reactive oxygen species increase during hypoxia (e.g., myocardial infarction [MI]) in skeletal muscle during the early phase of heart failure (HF) model mouse. Our results shed light on the pathogenic mechanism of skeletal muscle abnormalities in HF after MI. The use of XO inhibitors requires consideration of the time course of XO activity. Our results indicate that the timing of administration is very important to achieve maximum beneficial effects when using XO inhibitors.
• Transferrin-based radiolabeled probe predicts the sensitivity of human renal cancer cell lines to ferroptosis inducer erastin

  Yuki Shibata, Hironobu Yasui, Kei Higashikawa, Yuji Kuge

  Biochemistry and Biophysics Reports 26 100957  2405-5808 2021/02 [Refereed][Not invited]
   

  Ferroptosis induction has been recognized as a novel cancer therapeutic strategy. To effectively apply ferroptosis-targeting cancer therapy to individual patients, a diagnostic indicator for selecting this therapeutic strategy from a number of molecular targeting drugs is needed. However, to date, methods that can predict the efficacy of ferroptosis-targeting treatment have not been established yet. In this study, we focused on the iron metabolic pathway to develop a nuclear imaging technique for diagnosing the susceptibility of cancer cells to ferroptosis. As a nuclear probe, human transferrin (Tf) was labeled with Gallium-68 (68Ga) using 2-(p-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) as a chelator (68Ga-NOTA-Tf). Western blot assay and clonogenic survival assay with human renal cancer cell lines A498 and 786-O revealed that the protein expression level of transferrin receptor1 (TfR1) and sensitivity to a ferroptosis inducer, erastin, were correlated. A cellular uptake assay with 68Ga-NOTA-Tf revealed that the cancer cells sensitive to erastin highly internalized the 68Ga-NOTA-Tf. Furthermore, treatment with the TfR1 inhibitor ferristatin II reduced the cellular uptake of 68Ga-NOTA-Tf, indicating that the intracellular uptake of the probe was mediated by TfR1. These results suggest that 68Ga-NOTA-Tf can be useful in predicting the sensitivity of cancer cells to ferroptosis inducers.
• Preoperative Texture Analysis Using 11C-Methionine Positron Emission Tomography Predicts Survival after Surgery for Glioma

  Osamu Manabe, Shigeru Yamaguchi, Kenji Hirata, Kentaro Kobayashi, Hiroyuki Kobayashi, Shunsuke Terasaka, Takuya Toyonaga, Keiichi Magota, Yuji Kuge, Nagara Tamaki, Tohru Shiga, Kohsuke Kudo

  Diagnostics 11 (2) 189  2021/01/28 [Refereed][Not invited]
   

  Background: Positron emission tomography with 11C-methionine (MET) is well established in the diagnostic work-up of malignant brain tumors. Texture analysis is a novel technique for extracting information regarding relationships among surrounding voxels, in order to quantify their inhomogeneity. This study evaluated whether the texture analysis of MET uptake has prognostic value for patients with glioma. Methods: We retrospectively analyzed adults with glioma who had undergone preoperative metabolic imaging at a single center. Tumors were delineated using a threshold of 1.3-fold of the mean standardized uptake value for the contralateral cortex, and then processed to calculate the texture features in glioma. Results: The study included 42 patients (median age: 56 years). The World Health Organization classifications were grade II (7 patients), grade III (17 patients), and grade IV (18 patients). Sixteen (16.1%) all-cause deaths were recorded during the median follow-up of 18.8 months. The univariate analyses revealed that overall survival (OS) was associated with age (hazard ratio (HR) 1.04, 95% confidence interval (CI) 1.01–1.08, p = 0.0093), tumor grade (HR 3.64, 95% CI 1.63–9.63, p = 0.0010), genetic status (p < 0.0001), low gray-level run emphasis (LGRE, calculated from the gray-level run-length matrix) (HR 2.30 × 1011, 95% CI 737.11–4.23 × 1019, p = 0.0096), and correlation (calculated from the gray-level co-occurrence matrix) (HR 5.17, 95% CI 1.07–20.93, p = 0.041). The multivariate analyses revealed OS was independently associated with LGRE and correlation. The survival curves were also significantly different (both log-rank p < 0.05). Conclusion: Textural features obtained using preoperative MET positron emission tomography may compliment the semi-quantitative assessment for prognostication in glioma cases.
• Effects of feeding condition on the myocardial and hepatic accumulation of radioiodine-labeled BMIPP in mice

  Kazuaki Yamasaki, Songji Zhao, Mie Nishimura, Yoichi Shimizu, Nagara Tamaki, Hiroshi Takeda, Yuji Kuge

  Annals of Nuclear Medicine 35 (1) 59 - 64 0914-7187 2021/01 [Refereed][Not invited]
   

  OBJECTIVE: 123I-15-(p-iodophenyl)-3(R,S)-methylpentadecanoic acid ([123I]BMIPP), a fatty acid analog, is widely used for the diagnosis of cardiac diseases. Feeding condition is one of the important factors in the myocardial fatty acid uptake, which may also affect myocardial accumulation of [123I]BMIPP and image quality of [123I]BMIPP scintigraphy. However, the relationship between the myocardial accumulation of [123I]BMIPP and the feeding condition is not entirely clear. Therefore, we determined the myocardial accumulation of [125I]BMIPP in mice at various metabolic statuses induced by fasting in comparison with the hepatic accumulation. METHODS: Fed or fasted (6-, 12-, and 24-h fasted) mice were intravenously injected with [125I]BMIPP (35.2-75.0 kBq, 4 nmol). Radioactivities in the heart and liver were measured at 1, 5, 10, 30, 60, and 120 min after the injection (n = 5-15/time point for each group), and then, the heart-to-liver (H/L) ratios were calculated. RESULTS: The myocardial accumulation level of [125I]BMIPP in the fed group was almost the same as that in the 6-h-fasted group at each time point, although it was decreased by 12- and 24-h fasting. The H/L ratios of [125I]BMIPP accumulation level were significantly decreased by fasting (1.92 ± 0.22, 1.45 ± 0.13, 1.12 ± 0.13, and 0.91 ± 0.15 at 10 min, and 3.30 ± 0.62, 2.09 ± 0.35, 1.79 ± 0.34, and 1.27 ± 0.06 at 30 min after the injection, respectively, for the fed group and the 6-, 12-, and 24-h-fasted groups; p < 0.0001), largely owing to the increase in the hepatic accumulation level in the fasting groups. CONCLUSION: Although short-period (6 h) fasting did not affect the myocardial accumulation level of [125I]BMIPP, the hepatic accumulation level was increased. The present results indicate that the fed condition may provide higher-contrast images in myocardial [123I]BMIPP scintigraphy.
• Decreased Proteasomal Function Induces Neuronal Loss and Memory Impairment

  Utano Tomaru, Tomoki Ito, Yu Ohmura, Kei Higashikawa, Syota Miyajima, Ruka Tomatsu, Tsunehito Higashi, Akihiro Ishizu, Yuji Kuge, Mitsuhiro Yoshioka, Masanori Kasahara

  The American Journal of Pathology 191 (1) 144 - 156 0002-9440 2021/01 [Refereed][Not invited]
   

  Alzheimer disease (AD) is a progressive neurodegenerative disorder and the most common type of dementia worldwide. There is considerable evidence of age-related disruption of proteostasis being responsible for the development of AD. The proteasome is a multicatalytic enzyme complex that degrades both normal and damaged proteins, and an age-related decline in its activity has been implicated in age-related pathologies. Although proteasomal dysfunction is assumed to be a key AD hallmark, it remains unclear whether its role in disease onset is causative or secondary. In this study, we demonstrate that mice with proteasomal dysfunction exhibited memory impairment with associated neuronal loss, accumulation of phosphorylated tau, and activation of endoplasmic reticulum (ER) stress-related apoptosis pathways. Impaired proteasomal activity also activated ER stress-related apoptosis pathways in HT-22, a murine hippocampal neuronal cell line. HT-22 cell death, caused by proteasomal inhibition, was prevented by an inhibitor of c-Jun N-terminal kinase, an ER stress-related molecule. Collective evidence suggests that impaired proteasomal activity alters proteostasis, and subsequent ER stress-mediated pathways play pivotal roles in neuronal loss. Because aging decreases proteasomal function, age-related impairment of proteasomes may be involved in the development and progression of AD in elderly patients.
• Increased [18F]FMISO accumulation under hypoxia by multidrug-resistant protein 1 inhibitors

  Yoichi Shimizu, Yukihiro Nakai, Hiroyuki Watanabe, Shimpei Iikuni, Masahiro Ono, Hideo Saji, Yuji Kuge, Tsuneo Saga, Yuji Nakamoto

  EJNMMI Research 11 (1) 9  2021/01 [Refereed][Not invited]
   

  [¹⁸F]Fluoromisonidazole ([¹⁸F]FMISO) is a PET imaging probe widely used for the detection of hypoxia. We previously reported that [¹⁸F]FMISO is metabolized to the glutathione conjugate of the reduced form in hypoxic cells. In addition, we found that the [¹⁸F]FMISO uptake level varied depending on the cellular glutathione conjugation and excretion ability such as enzyme activity of glutathione-S-transferase and expression levels of multidrug resistance-associated protein 1 (MRP1, an efflux transporter), in addition to the cellular hypoxic state. In this study, we evaluated whether MRP1 activity affected [¹⁸F]FMISO PET imaging. FaDu human pharyngeal squamous cell carcinoma cells were pretreated with MRP1 inhibitors (cyclosporine A, lapatinib, or MK-571) for 1 h, incubated with [¹⁸F]FMISO for 4 h under hypoxia, and their radioactivity was then measured. FaDu tumor-bearing mice were intravenously injected with [¹⁸F]FMISO, and PET/CT images were acquired at 4 h post-injection (1st PET scan). Two days later, the same mice were pretreated with MRP1 inhibitors (cyclosporine A, lapatinib, or MK-571) for 1 h, and PET/CT images were acquired (2nd PET scan). FaDu cells pretreated with MRP1 inhibitors exhibited significantly higher radioactivity than those without inhibitor treatment (cyclosporine A: 6.91 ± 0.27, lapatinib: 10.03 ± 0.47, MK-571: 10.15 ± 0.44%dose/mg protein, p < 0.01). In the in vivo PET study, the SUV_mean ratio in tumors [calculated as after treatment (2nd PET scan)/before treatment of MRP1 inhibitors (1st PET scan)] of the mice treated with MRP1 inhibitors was significantly higher than those of control mice (cyclosporine A: 2.6 ± 0.7, lapatinib: 2.2 ± 0.7, MK-571: 2.2 ± 0.7, control: 1.2 ± 0.2, p < 0.05). In this study, we revealed that MRP1 inhibitors increase [¹⁸F]FMISO accumulation in hypoxic cells. This suggests that [¹⁸F]FMISO-PET imaging is affected by MRP1 inhibitors independent of the hypoxic state.
• Characterization of brown adipose tissue thermogenesis in the naked mole-rat (Heterocephalus glaber), a heterothermic mammal

  Yuki Oiwa, Kaori Oka, Hironobu Yasui, Kei Higashikawa, Hidemasa Bono, Yoshimi Kawamura, Shingo Miyawaki, Akiyuki Watarai, Takefumi Kikusui, Atsushi Shimizu, Hideyuki Okano, Yuji Kuge, Kazuhiro Kimura, Yuko Okamatsu-Ogura, Kyoko Miura

  Scientific Reports 10 (1) 19488  2020/12 [Refereed][Not invited]
   

  The naked mole-rat (NMR) is a heterothermic mammal that forms eusocial colonies consisting of one reproductive female (queen), several reproductive males, and subordinates. Despite their heterothermy, NMRs possess brown adipose tissue (BAT), which generally induces thermogenesis in cold and some non-cold environments. Previous studies suggest that NMR-BAT induces thermogenesis by cold exposure. However, detailed NMR-BAT characteristics and whether NMR-BAT thermogenesis occurs in non-cold environments are unknown. Here, we show beta-3 adrenergic receptor (ADRB3)-dependent thermogenic potential of NMR-BAT, which contributes to thermogenesis in the isolated queen in non-cold environments (30 °C). NMR-BAT expressed several brown adipocyte marker genes and showed noradrenaline-dependent thermogenic activity in vitro and in vivo. Although our ADRB3 inhibition experiments revealed that NMR-BAT thermogenesis slightly delays the decrease in body temperature in a cold environment (20 °C), it was insufficient to prevent the decrease in the body temperatures. Even at 30 °C, NMRs are known to prevent the decrease of and maintain their body temperature by heat-sharing behaviors within the colony. However, isolated NMRs maintained their body temperature at the same level as when they are in the colony. Interestingly, we found that queens, but not subordinates, induce BAT thermogenesis in this condition. Our research provides novel insights into NMR thermoregulation.
• Influence of the scan time point when assessing hypoxia in 18F-fluoromisonidazole PET: 2 vs. 4 h.

  Kentaro Kobayashi, Osamu Manabe, Kenji Hirata, Shigeru Yamaguchi, Hiroyuki Kobayashi, Shunsuke Terasaka, Takuya Toyonaga, Sho Furuya, Keiichi Magota, Yuji Kuge, Kohsuke Kudo, Tohru Shiga, Nagara Tamaki

  European journal of nuclear medicine and molecular imaging 47 (8) 1833 - 1842 2020/07 [Refereed][Not invited]
   

  PURPOSE: 18F-fluoromisonidazole (18F-FMISO) is the most widely used positron emission tomography (PET) tracer for imaging tumor hypoxia. Previous reports suggested that the time from injection to the scan may affect the assessment of 18F-FMISO uptake. Herein, we directly compared the images at 2 h and 4 h after a single injection of 18F-FMISO. METHODS: Twenty-three patients with or suspected of having a brain tumor were scanned twice at 2 and 4 h following an intravenous injection of 18F-FMISO. We estimated the mean standardized uptake value (SUV) of the gray matter and white matter and the gray-to-white matter ratio in the background brain tissue from the two scans. We also performed a semi-quantitative analysis using the SUVmax and maximum tumor-to-normal ratio (TNR) for the tumor. RESULTS: At 2 h, the SUVmean of gray matter was significantly higher than that of white matter (median 1.23, interquartile range (IQR) 1.10-1.32 vs. 1.04, IQR 0.95-1.16, p < 0.0001), whereas at 4 h, it significantly decreased to approach that of the white matter (1.10, IQR 1.00-1.23 vs. 1.02, IQR 0.93-1.13, p = NS). The gray-to-white matter ratio thus significantly declined from 1.17 (IQR 1.14-1.19) to 1.09 (IQR 1.07-1.10) (p < 0.0001). All 7 patients with glioblastoma showed significant increases in the SUVmax (2.20, IQR 1.67-3.32 at 2 h vs. 2.65, IQR 1.74-4.41 at 4 h, p = 0.016) and the TNR (1.75, IQR 1.40-2.38 at 2 h vs. 2.34, IQR 1.67-3.60 at 4 h, p = 0.016). CONCLUSION: In the assessment of hypoxic tumors, 18F-FMISO PET for hypoxia imaging should be obtained at 4 h rather than 2 h after the injection.
• Association of Hydrophobic Carboxyl-Terminal Dendrimers with Lymph Node-Resident Lymphocytes.

  Yutaka Nishimoto, Misaki Nishio, Shu Nagashima, Kohei Nakajima, Takayuki Ohira, Shinya Nakai, Ikuhiko Nakase, Kei Higashikawa, Yuji Kuge, Akikazu Matsumoto, Mikako Ogawa, Chie Kojima

  Polymers 12 (7) 2020/06/30 [Refereed][Not invited]
   

  Delivery systems to lymph node-resident T cells around tumor tissues are essential for cancer immunotherapy, in order to boost the immune responses. We previously reported that anionic dendrimers, such as carboxyl-, sulfonyl-, and phosphate-terminal dendrimers, were efficiently accumulated in lymph nodes via the intradermal injection. Depending on the terminal structure, their cell association properties were different, and the carboxyl-terminal dendrimers did not associate with any immune cells majorly. In this study, we investigated the delivery of carboxyl-terminal dendrimers with different hydrophobicity to lymph node-resident lymphocytes. Four types of carboxyl-terminal dendrimers-succinylated (C) and 2-carboxy-cyclohexanoylated (Chex) dendrimers with and without phenylalanine (Phe)-were synthesized and named C-den, C-Phe-den, Chex-den, and Chex-Phe-den, respectively. Chex-Phe-den was well associated with lymphocytes, but others were not. Chex-Phe-den, intradermally injected at the footpads of mice, was accumulated in the lymph node, and was highly associated with the lymphocytes, including T cells. Our results suggest that Chex-Phe-den has the potential for delivery to the lymph node-resident T cells, without any specific T cell-targeted ligands.
• Biodistribution and internal radiation dosimetry of a novel probe for thymidine phosphorylase imaging, [123I]IIMU, in healthy volunteers.

  Shiro Watanabe, Ken-Ichi Nishijima, Shozo Okamoto, Keiichi Magota, Kenji Hirata, Takuya Toyonaga, Tohru Shiga, Yuji Kuge, Nagara Tamaki

  Annals of nuclear medicine 34 (8) 595 - 599 2020/05/02 [Refereed][Not invited]
   

  OBJECTIVE: We evaluated the radiation dosage, biodistribution, human safety, and tolerability of the injection of a single dose of [123I] 5-iodo-6-[(2-iminoimidazolidinyl)methyl]uracil (IIMU), a new radiotracer targeting thymidine phosphorylase (TP), in healthy volunteers. METHODS: Potential participants were tested at our hospital to confirm their eligibility. Two healthy male adults passed the screening tests. They were injected with 56 and 111 MBq of [123I]IIMU, respectively. Safety assessments were performed before and at 1, 3, 6, 9, 24, 48 h, and 1-week post-injection. Whole-body emission scans were conducted at 1, 3, 6, 24, and 48 h post-injection. Regions of interest were manually drawn to enclose the entire body at each time point, identifying high-uptake organs to obtain the time-activity curves. Urine and blood samples were collected at 1, 2, 3, 4, 5, 6, 9, 24, and 48 h post-injection. The radiation dose for each organ and the effective doses were estimated using OLINDA/EXM 1.1 software. RESULTS: No adverse events were observed as of the follow-up visit > 1-week post-injection. In both subjects, the highest uptake of [123I]IIMU occurred in the liver, with peak injected activity (%IA) values of 17.7% and 15.1%, respectively. The second highest uptake was in the thyroid (0.35% and 0.66% IA). The %IA decreased gradually toward the end of the study (48 h) in all organs except the liver and thyroid. By the end of the study, 52.5% and 51.5% of the injected activity of [123I]IIMU had been excreted via the subjects' renal systems. The estimated mean effective doses of [123I]IIMU were 9.19 μSv/MBq and 10.1 μSv/MBq, respectively. CONCLUSION: In this preliminary study, [123I]IIMU was safely administered to healthy adults, and its potential clinical use in TP imaging was revealed.
• Influence on [18F]FDG uptake by cancer cells after anti-PD-1 therapy in an enforced-immune activated mouse tumor.

  Mayu Tomita, Motofumi Suzuki, Yusuke Kono, Kohei Nakajima, Takuma Matsuda, Yuji Kuge, Mikako Ogawa

  EJNMMI research 10 (1) 24 - 24 2020/03/19 [Refereed][Not invited]
   

  BACKGROUND: Anti-programmed cell death 1 (PD-1) antibody is an immune checkpoint inhibitor, and anti-PD-1 therapy improves the anti-tumor functions of T cells and affects tumor microenvironment. We previously reported that anti-PD-1 treatment affected tumor glycolysis by using 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) positron emission tomography (PET). That study showed that anti-PD-1 therapy in a mouse B16F10 melanoma model increased glucose metabolism in cancer cells at the point where anti-PD-1 therapy did not cause a significant inhibition of tumor growth. However, the B16F10 melanoma model is poorly immunogenic, so it is not clear how anti-PD-1 treatment affects glucose metabolism in highly immunogenic cancer models. In this study, we used a cyclic dinucleotide GMP-AMP (cGAMP)-injected B16F10 melanoma model to investigate the effect of anti-PD-1 therapy on [18F]FDG uptake in a highly immune activated tumor in mice. RESULTS: To compare the cGAMP-injected B16F10 model with the B16F10 model, experiments were performed as described in our previous manuscript. [18F]FDG-PET was measured before treatment and 7 days after the start of treatment. In this study, [18F]FDG uptake in tumors in the cGAMP/anti-PD-1 combination group was lower than that in the anti-PD-1 treatment group tumors on day 7, as shown by PET and ex vivo validation. Flow-cytometry was performed to assess immune cell populations and glucose metabolism. Anti-PD-1 and/or cGAMP treatment increased the infiltration level of immune cells into tumors. The cGAMP/anti-PD-1 combination group had significantly lower levels of GLUT1high cells/hexokinase IIhigh cells in CD45- cancer cells compared with tumors in the anti-PD-1 treated group. These results suggested that if immune responses in tumors are higher than a certain level, glucose uptake in cancer cells is reduced depending on that level. Such a change of glucose uptake might be caused by the difference in infiltration or activation level of immune cells between the anti-PD-1 treated group and the cGAMP/anti-PD-1 combination group. CONCLUSIONS: [18F]FDG uptake in cancer cells after anti-PD-1 treatment might be affected by the tumor immune microenvironment including immune cell infiltration, composition, and activation status.
• FTY720 Protects Against Ischemia-Reperfusion Injury by Preventing the Redistribution of Tight Junction Proteins and Decreases Inflammation in the Subacute Phase in an Experimental Stroke Model.

  Zifeng Wang, Kei Higashikawa, Hironobu Yasui, Yuji Kuge, Yusuke Ohno, Akio Kihara, Yenari A Midori, Kiyohiro Houkin, Masahito Kawabori

  Translational stroke research 11 (5) 1103 - 1116 2020/02/27 [Refereed][Not invited]
   

  Injury due to brain ischemia followed by reperfusion (I/R) may be an important therapeutic target in the era of thrombectomy. FTY720, a widely known sphingosine-1-phosphate receptor agonist, exerts various neuroprotective effects. The aim of this study was to examine the protective effect of FTY720 with respect to I/R injury, especially focusing on blood-brain barrier (BBB) protection and anti-inflammatory effects. Male rats were subjected to transient ischemia and administered vehicle or 0.5 or 1.5 mg/kg of FTY720 immediately before reperfusion. Positron emission tomography (PET) with [18F]DPA-714 was performed 2 and 9 days after the insult to serially monitor neuroinflammation. Bovine and rat brain microvascular endothelial cells (MVECs) were also subjected to oxygen-glucose deprivation (OGD) and reperfusion, and administered FTY720, phosphorylated-FTY720 (FTY720-P), or their inhibitor. FTY720 dose-dependently reduced cell death, the infarct size, cell death including apoptosis, and inflammation. It also ameliorated BBB disruption and neurological deficits compared to in the vehicle group. PET indicated that FTY720 significantly inhibited the worsening of inflammation in later stages. FTY720-P significantly prevented the intracellular redistribution of tight junction proteins but did not increase their mRNA expression. These results suggest that FTY720 can ameliorate I/R injury by protecting the BBB and regulating neuroinflammation.
• Carboxyl-, sulfonyl-, and phosphate-terminal dendrimers as a nanoplatform with lymph node targeting

  Nishimoto Y, Nagashima S, Nakajima K, Ohira T, Sato T, Izawa T, Yamate J, Higashikawa K, Kuge Y, Ogawa M, Kojima C

  Int J Pharm. 576 119021  2020 [Refereed][Not invited]
  
• Preclinical investigation of potential use of thymidine phosphorylase-targeting tracer for diagnosis of nonalcoholic steatohepatitis.

  Kei Higashikawa, Sawako Horiguchi, Makoto Tarisawa, Yuki Shibata, Kazue Ohkura, Hironobu Yasui, Hiroshi Takeda, Yuji Kuge

  Nuclear medicine and biology 82-83 25 - 32 0969-8051 2019/12/16 [Refereed][Not invited]
   

  INTRODUCTION: Although liver biopsy is the gold standard for the diagnosis of nonalcoholic steatohepatitis (NASH), it has several problems including high invasiveness and sampling errors. Therefore, the development of alternative methods to overcome these disadvantages is strongly required. In this study, we evaluated the potential use of our tracer targeting thymidine phosphorylase (TYMP), 5-[123I]iodo-6-[(2-iminoimidazolidinyl)methyl]uracil ([123I]IIMU) for the diagnosis of NASH. METHODS: The mice used as the NASH model (hereafter, NASH mice) were prepared by feeding a methionine- and choline-deficient diet for 4 weeks. A control group was similarly given a control diet. The expression levels of the TYMP gene and protein in the liver were examined by real-time reverse-transcription polymerase chain reaction and western blot analyses. The localizations of [125I]IIMU and the TYMP protein in the liver were examined by autoradiography and immunohistochemical staining, respectively. Finally, the mice were injected with [123I]IIMU and single-photon emission tomography (SPECT) imaging was conducted. RESULTS: The hepatic expression levels of TYMP were significantly lower in the NASH mice than in the control mice at both mRNA and protein levels, suggesting that a decrease in TYMP level could be an indicator of NASH. [125I]IIMU was uniformly distributed in the liver of the control mice, whereas it showed a patchy distribution in that of the NASH mice. The localization of [125I]IIMU was visually consistent with that of the TYMP protein in the liver of the control and NASH mice. SPECT analysis indicated that the hepatic accumulation of [123I]IIMU in the NASH mice was significantly lower than that in the control mice [SUV (g/ml): 4.14 ± 0.87 (Control) vs 2.31 ± 0.29 (NASH)]. CONCLUSIONS: [123I]IIMU may provide a noninvasive means for imaging TYMP expression in the liver and may be applicable to the diagnosis of NASH.
• 18F-FMISO PET/CT detects hypoxic lesions of cardiac and extra-cardiac involvement in patients with sarcoidosis.

  Sho Furuya, Masanao Naya, Osamu Manabe, Kenji Hirata, Hiroshi Ohira, Tadao Aikawa, Kazuhiro Koyanagawa, Keiichi Magota, Ichizo Tsujino, Toshihisa Anzai, Yuji Kuge, Noriko Oyama-Manabe, Kohsuke Kudo, Tohru Shiga, Nagara Tamaki

  Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology 2019/12/09 [Refereed][Not invited]
   

  BACKGROUND: 18F-fluoromisonidazole (FMISO) is a hypoxia positron emission tomography (PET) tracer. Here, we evaluated cardiac and extra-cardiac sarcoidosis using both FMISO and 18F-fluorodeoxyglucose (FDG) PET/CT in a prospective cohort of patients with sarcoidosis. METHODS: Ten consecutive sarcoidosis patients with suspected cardiac involvement were prospectively enrolled. Each patient fasted overnight (for ≥ 18 hours) preceded by a low-carbohydrate diet before FDG PET/CT but not given special dietary instructions before the FMISO PET/CT scan. We visually and semiquantitatively assessed the uptakes of FMISO and FDG using the maximal standardized uptake value (SUVmax). The metabolic volume (MV) of FDG was calculated as the volume within the boundary determined by the threshold (mean SUV of blood pool × 1.5). RESULTS: Nine patients showed focal FDG uptake in the myocardium and were diagnosed with cardiac sarcoidosis. Among the patients with extra-cardiac lesions, FDG uptake was seen in 8 lymph nodes and 3 lung lesions. FMISO uptake was seen in the 7 cardiac (77.8%) and 6 extra-cardiac (54.5%) lesions. None of the patients showed physiological FMISO uptake in the myocardium. The SUVmax values of the lesions with FMISO uptake were higher than those of the lesions without FMISO uptake in both the cardiac (SUVmax: 9.9, IQR: 8.4-10.0 vs 7.3, IQR: 6.3-8.2) and non-cardiac lesions (SUVmax: 17.6, IQR: 14.5-19.3 vs 6.1, IQR: 5.9-6.2; P = 0.006). The MV values of the lesions with FMISO uptake were significantly higher than those of the lesions without FMISO uptake (111.3, IQR: 78.3-135.7 vs 6.4, IQR: 1.9-23.3; P = 0.0009). CONCLUSIONS: FMISO showed no physiological myocardial uptake and did not require special preparation. FMISO PET has the potential to detect hypoxic lesions in patients with sarcoidosis.
• Combination of FDG-PET and FMISO-PET as a treatment strategy for patients undergoing early-stage NSCLC stereotactic radiotherapy.

  Shiro Watanabe, Tetsuya Inoue, Shozo Okamoto, Keiichi Magota, Ayumi Takayanagi, Jun Sakakibara-Konishi, Norio Katoh, Kenji Hirata, Osamu Manabe, Takuya Toyonaga, Yuji Kuge, Hiroki Shirato, Nagara Tamaki, Tohru Shiga

  EJNMMI research 9 (1) 104  2019/12/04 [Refereed][Not invited]
   

  BACKGROUND: We investigated the prognostic predictive value of the combination of fluorodeoxyglucose (FDG)- and fluoromisonidazole (FMISO)-PET in patients with non-small cell lung carcinoma (NSCLC) treated with stereotactic body radiation therapy (SBRT). PATIENTS AND METHODS: We prospectively examined patients with pathologically proven NSCLC; all underwent FDG and FMISO PET/CT scans before SBRT. PET images were acquired using a whole-body time-of-flight PET-CT scanner with respiratory gating. We classified them into recurrent and non-recurrent groups based on their clinical follow-ups and compared the groups' tumor diameters and PET parameters (i.e., maximum of the standardized uptake value (SUVmax), metabolic tumor volume, tumor-to-muscle ratio, and tumor-to-blood ratio). We performed univariate analysis to evaluate the impact of the PET variables on the patients' progression-free survival (PFS). We divided the patients by thresholds of FDG SUVmax and FMISO SUVmax obtained from receiver operating characteristic analysis for assessment of recurrence rate and PFS. RESULTS: Thirty-two NSCLC patients (19 male and 13 females; median age, 83 years) were enrolled. All received SBRT. At the study endpoint, 23 patients (71.9%) were non-recurrent and nine patients (28.1%) had recurrent disease. Significant between-group differences were observed in tumor diameter and all the PET parameters, demonstrating that those were significant predictors of the recurrence in all patients. In the 22 patients with tumors > 2 cm, tumor diameter and FDG SUVmax were not significant predictors. Thirty-two patients were divided into three patterns from the thresholds of FDG SUVmax (6.81) and FMISO SUVmax (1.89); A, low FDG and low FMISO (n = 14); B, high FDG and low FMISO (n = 8); C, high FDG and high FMISO (n = 10). No pattern A patient experienced tumor recurrence, whereas two pattern B patients (25%) and seven pattern C patients (70%) exhibited recurrence. A Kaplan-Meier analysis of all patients revealed a significant difference in PFS between patterns A and B (p = 0.013) and between patterns A and C (p < 0.001). In the tumors > 2 cm patients, significant differences in PFS were demonstrated between pattern A and C patients (p = 0.002). CONCLUSION: The combination of FDG- and FMISO-PET can identify patients with a baseline risk of recurrence and indicate whether additional therapy might be performed to improve survival.
• Biodistribution and radiation dosimetry of the novel hypoxia PET probe [18F]DiFA and comparison with [18F]FMISO.

  Shiro Watanabe, Tohru Shiga, Kenji Hirata, Keiichi Magota, Shozo Okamoto, Takuya Toyonaga, Kei Higashikawa, Hironobu Yasui, Jun Kobayashi, Ken-Ichi Nishijima, Ken Iseki, Hiroki Matsumoto, Yuji Kuge, Nagara Tamaki

  EJNMMI research 9 (1) 60 - 60 2019/07/05 [Refereed][Not invited]
   

  BACKGROUND: To facilitate hypoxia imaging in a clinical setting, we developed 1-(2,2-dihydroxymethyl-3-[18F]-fluoropropyl)-2-nitroimidazole ([18F]DiFA) as a new tracer that targets tumor hypoxia with its lower lipophilicity and efficient radiosynthesis. Here, we evaluated the radiation dosage, biodistribution, human safety, tolerability, and early elimination after the injection of [18F]DiFA in healthy subjects, and we performed a preliminary clinical study of patients with malignant tumors in a comparison with [18F]fluoromisonidazole ([18F]FMISO). RESULTS: The single administration of [18F]DiFA in 8 healthy male adults caused neither adverse events nor abnormal clinical findings. Dynamic and sequential whole-body scans showed that [18F]DiFA was rapidly cleared from all of the organs via the hepatobiliary and urinary systems. The whole-body mean effective dose of [18F]DiFA estimated by using the medical internal radiation dose (MIRD) schema with organ level internal dose assessment/exponential modeling (OLINDA/EXM) computer software 1.1 was 14.4 ± 0.7 μSv/MBq. Among the organs, the urinary bladder received the largest absorbed dose (94.7 ± 13.6 μSv/MBq). The mean absorbed doses of the other organs were equal to or less than those from other hypoxia tracers. The excretion of radioactivity via the urinary system was very rapid, reaching 86.4 ± 7.1% of the administered dose. For the preliminary clinical study, seven patients were subjected to [18F]FMISO and [18F]DiFA positron emission tomography (PET) at 48-h intervals to compare the two tracers' diagnostic ability for tumor hypoxia. The results of the tumor hypoxia evaluation by [18F]DiFA PET at 1 h and 2 h were not significantly different from those obtained with [18F]FMISO PET at 4 h ([18F]DiFA at 1 h, p = 0.32; [18F]DiFA at 2 h, p = 0.08). Moreover, [18F]DiFA PET at both 1 h (k = 0.68) and 2 h (k = 1.00) showed better inter-observer reproducibility than [18F]FMISO PET at 4 h (k = 0.59). CONCLUSION: [18F]DiFA is well tolerated, and its radiation dose is comparable to those of other hypoxia tracers. [18F]DiFA is very rapidly cleared via the urinary system. [18F]DiFA PET generated comparable images to [18F]FMISO PET in hypoxia imaging with shorter waiting time, demonstrating the promising potential of [18F]DiFA PET for hypoxia imaging and for a multicenter trial.
• Elimination of tumor hypoxia by eribulin demonstrated by 18F-FMISO hypoxia imaging in human tumor xenograft models.

  Songji Zhao, Wenwen Yu, Naoyuki Ukon, Chengbo Tan, Ken-Ichi Nishijima, Yoichi Shimizu, Kei Higashikawa, Tohru Shiga, Hiroko Yamashita, Nagara Tamaki, Yuji Kuge

  EJNMMI research 9 (1) 51 - 51 2019/06/03 [Refereed][Not invited]
   

  BACKGROUND: Eribulin, an inhibitor of microtubule dynamics, shows antitumor potency against a variety of solid cancers through its antivascular activity and remodeling of tumor vasculature. 18F-Fluoromisonidazole (18F-FMISO) is the most widely used PET probe for imaging tumor hypoxia. In this study, we utilized 18F-FMISO to clarify the effects of eribulin on the tumor hypoxic condition in comparison with histological findings. MATERIAL AND METHODS: Mice bearing a human cancer cell xenograft were intraperitoneally administered a single dose of eribulin (0.3 or 1.0 mg/kg) or saline. Three days after the treatment, mice were injected with 18F-FMISO and pimonidazole (hypoxia marker for immunohistochemistry), and intertumoral 18F-FMISO accumulation levels and histological characteristics were determined. PET/CT was performed pre- and post-treatment with eribulin (0.3 mg/kg, i.p.). RESULTS: The 18F-FMISO accumulation levels and percent pimonidazole-positive hypoxic area were significantly lower, whereas the number of microvessels was higher in the tumors treated with eribulin. The PET/CT confirmed that 18F-FMISO distribution in the tumor was decreased after the eribulin treatment. CONCLUSIONS: Using 18F-FMISO, we demonstrated the elimination of the tumor hypoxic condition by eribulin treatment, concomitantly with the increase in microvessel density. These findings indicate that PET imaging using 18F-FMISO may provide the possibility to detect the early treatment response in clinical patients undergoing eribulin treatment.
• Comparative evaluation of [18F]DiFA and its analogs as novel hypoxia positron emission tomography and [18F]FMISO as the standard.

  Norihito Nakata, Masato Kiriu, Yuki Okumura, Songji Zhao, Ken-Ichi Nishijima, Tohru Shiga, Nagara Tamaki, Yuji Kuge, Hiroki Matsumoto

  Nuclear medicine and biology 70 39 - 45 2019/03 [Refereed][Not invited]
   

  INTRODUCTION: Hypoxia, a common feature of most solid tumors, is an important predictor of tumor progression and resistance to radiotherapy. We developed a novel hypoxia imaging probe with optimal biological characteristics for use in clinical settings. METHODS: We designed and synthesized several new hypoxia probes with additional hydrophilic characteristics compared to [18F]fluoromisonidazole ([18F]FMISO). These were 1-(2,2-Dihydroxy-methyl-3-[18F]-Fluoropropyl) azomycin ([18F]DiFA, formerly [18F]HIC101) and its analogs ([18F]F1 and [18F]F2). Biodistribution studies with EMT6 mammary carcinoma cell-bearing mice were performed 1 and 2 h after injection of each probe. Small-animal positron emission tomography (PET) imaging studies were conducted using [18F]DiFA and [18F]FMISO in the same mice. Tumoral hypoxia was confirmed via pimonidazole staining. Ex vivo digital autoradiographs were obtained for confirming the co-localization of [18F]DiFA and pimonidazole in the tumor tissues. RESULTS: The EMT6 tumors used had pimonidazole-positive regions. In biodistribution studies, the tumor-to-blood ratio and tumor-to-muscle ratio of [18F]DiFA was significantly higher than the respective [18F]FMISO ratios 1 h after injection. Hence, we selected [18F]DiFA as the best hypoxia probe among those tested. Small-animal PET imaging studies showed time-dependent increases in the tumor-to-normal tissue ratio of [18F]DiFA uptake. Rapid clearance from the rest of the body was observed primarily via the renal system. Ex vivo autoradiography showed a positive correlation between [18F]DiFA uptake and the regions of pimonidazole distribution, indicating that [18F]DiFA selectively accumulated in the tumor tissue's hypoxic region. CONCLUSIONS: A better contrast image and a shorter waiting time may be obtained with [18F]DiFA than with [18F]FMISO. ADVANCES IN KNOWLEDGE: By optimizing LogP based on the [18F]FMISO structure, we demonstrated that [18F]DiFA could detect tumor hypoxia regions at an early time point. IMPLICATIONS FOR PATIENT CARE: [18F]DiFA imaging facilitates the evaluation of various cancer hypoxic states due to the lower uptake of normal tissues and could contribute to novel treatment development.
• A Novel PET Probe "[18F]DiFA" Accumulates in Hypoxic Region via Glutathione Conjugation Following Reductive Metabolism.

  Yoichi Shimizu, Songji Zhao, Hironobu Yasui, Ken-Ichi Nishijima, Hiroki Matsumoto, Tohru Shiga, Nagara Tamaki, Mikako Ogawa, Yuji Kuge

  Molecular imaging and biology 21 (1) 122 - 129 2019/02 [Refereed][Not invited]
   

  PURPOSE: Hypoxia in tumor has close relationship with angiogenesis and tumor progression. Previously, we developed 2,2-dihydroxymethyl-3-[18F]fluoropropyl-2-nitroimidazole ([18F]DiFA) as a novel positron emission tomography (PET) probe for diagnosis of hypoxia. In this study, we elucidated whether the accumulation of [18F]DiFA in cells is dependent on the hypoxic state and revealed how [18F]DiFA accumulates in hypoxic cells in combination with imaging mass spectrometry (IMS). PROCEDURES: FaDu human head and neck cancer cells were treated with [18F]DiFA and then incubated under normoxia (21% O2) or hypoxia (1% O2) for 2 h. The cells were extracted using methanol, and the radioactivities of the precipitates (macromolecule fraction) and supernatants (low-molecular-weight fraction) were measured. FaDu-bearing mice were injected intravenously with [18F]DiFA and with pimonidazole 1 h later. The tumors were excised 2 h after the injection of [18F]DiFA. Autoradiography, IMS, and immunohistochemical (IHC) staining for pimonidazole were performed with serial tumor sections. RESULTS: In the in vitro study, the radioactivity of FaDu cells was significantly higher under hypoxia than that under normoxia (0.53 ± 0.02 vs. 0.27 ± 0.02 %dose/mg protein, p < 0.05). The radioactivity of the low-molecular-weight fraction was 66.3 ± 0.6% in the hypoxic cell. In the in vivo study, [18F]DiFA accumulated in the tumor tissues existed mainly as low-molecular-weight compounds (90.4 ± 0.9%). In addition, the glutathione conjugate of reductive DiFA metabolite (amino-DiFA-GS) existed in tumor tissues revealed by the IMS study, and the distribution pattern of amino-DiFA-GS was very similar to that of the radioactivity and the positive staining area of pimonidazole. CONCLUSIONS: Our results suggest that [18F]DiFA undergoes the glutathione conjugation reaction following reductive metabolism in hypoxic cells, which leads hypoxia-specific PET imaging with [18F]DiFA.
• Erastin, a ferroptosis-inducing agent, sensitized cancer cells to X-ray irradiation via glutathione starvation in vitro and in vivo.

  Shibata Y, Yasui H, Higashikawa K, Miyamoto N, Kuge Y

  PloS one 14 (12) e0225931  2019 [Refereed][Not invited]
  
• Glutathione and cysteines suppress cytotoxicity of gas phase of cigarette smoke by direct reacting with unsaturated carbonyl compounds in the gas phase.

  Higashi T, Elmeligy E, Mai Y, Noya Y, Terada K, Mazaki Y, Kuge Y, Miwa S

  Biochem Biophys Res Commun. 509 (4) 988 - 993 2019 [Refereed][Not invited]
   

  Unsaturated carbonyl compounds, such as acrolein (ACR) and methyl vinyl ketone (MVK), are environmental pollutants, and are contained in smoke, automobile exhaust, and heated oil. We have previously reported that major cytotoxic factors in the gas phase of cigarette smoke are ACR and MVK. ACR and MVK induce cell damage by reactive oxygen species generation via protein kinase C and NADPH oxidases, and antioxidants, such as glutathione (GSH) and N-acetylcysteine (NAC), can effectively suppress their cytotoxic activities. In this study, we attempted to elucidate the molecular mechanism(s) for suppression of ACR- and MVK-induced cytotoxic activities by these antioxidants. GSH, NAC, L- and D-cysteines completely suppressed cell damage induced by gas phase extract of cigarette smoke. The results of HPLC and mass spectrometry showed that GSH and NAC directly reacted with ACR and MVK. Cysteines and cysteine derivatives suppressed ACR-induced GAPDH carbonylation, a representative protein for carbonylation. The current results suggest that GSH, NAC, and cysteines directly reacted with ACR and MVK, and suppressed these unsaturated carbonyl compounds-induced cell damage by inhibition of protein carbonylation.
• Voxel based comparison and texture analysis of 18F-FDG and 18F-FMISO PET of patients with head-and-neck cancer.

  Kroenke M, Hirata K, Gafita A, Watanabe S, Okamoto S, Magota K, Shiga T, Kuge Y, Tamaki N

  PLoS One 14 (2) e0213111  2019 [Refereed][Not invited]
   

  BACKGROUND: Hypoxia can induce radiation resistance and is an independent prognostic marker for outcome in head and neck cancer. As 18F-FMISO (FMISO), a hypoxia tracer for PET, is far less common than 18F-FDG (FDG) and two separate PET scans result in doubled cost and radiation exposure to the patient, we aimed to predict hypoxia from FDG PET with new techniques of voxel based analysis and texture analysis. METHODS: Thirty-eight patients with head-and-neck cancer underwent consecutive FDG and FMISO PET scans before any treatment. ROIs enclosing the primary cancer were compared in a voxel-by-voxel manner between FDG and FMISO PET. Tumour hypoxia was defined as the volume with a tumour-to-muscle ratio (TMR) > 1.25 in the FMISO PET and hypermetabolic volume was defined as >50% SUVmax in the FDG PET. The concordance rate was defined as percentage of voxels within the tumour which were both hypermetabolic and hypoxic. 38 different texture analysis (TA) parameters were computed based on the ROIs and correlated with presence of hypoxia. RESULTS: Within the hypoxic tumour regions, the FDG uptake was twice as high as in the non-hypoxic tumour regions (SUVmean 10.9 vs. 5.4; p<0.001). A moderate correlation between FDG and FMISO uptake was found by a voxel-by-voxel comparison (r = 0.664 p<0.001). The average concordance rate was 25% (± 22%). Entropy was the TA parameter showing the highest correlation with hypoxia (r = 0.524 p<0.001). CONCLUSION: FDG uptake was higher in hypoxic tumour regions than in non-hypoxic regions as expected by tumour biology. A moderate correlation between FDG and FMISO PET was found by voxel-based analysis. TA yielded similar results in FDG and FMISO PET. However, it may not be possible to predict tumour hypoxia even with the help of texture analysis.
• Accumulation of hypoxia imaging probe "18F-FMISO" in macrophages depends on macrophage polarization in addition to hypoxic state.

  Shimizu Y, Motomura A, Takakura H, Tamaki N, Kuge Y, Ogawa M

  Ann Nucl Med. 33 (5) 362 - 367 2019 [Refereed][Not invited]
   

  OBJECTIVE: Macrophages play an essential role in immune response, and are closely related to the progression of diseases such as cancer and atherosclerosis. Macrophages polarize to M1 or M2 type, which is related to the environmental hypoxic state. Previously, we found that 18F-FMISO uptake varied according to expression levels of biomolecules such as glutathione S-transferase P1 (GST-P1), which catalyzes the conjugation of glutathione to 18F-FMISO metabolites, and multidrug resistance-associated protein 1 (MRP1), which exports glutathione-18F-FMISO metabolite conjugates out of cells. However, the relationship between macrophage polarization and 18F-FMISO accumulation remains unclear. METHODS: Mouse peritoneal macrophages were polarized to either the M1 or M2 type, and were treated with 18F-FMISO. Then, their radioactivity after a 4 h incubation period under normoxic (21% O2) or hypoxic (1% O2) condition was measured. GST-P1 and MRP1 expression levels were measured by qRT-PCR. RESULTS: M2 macrophages exhibited a significantly higher uptake of 18F-FMISO than non-polarized (M0) macrophages, whereas M1 macrophages had a significantly lower uptake than M0 macrophages (M0: 1.05 ± 0.22, M1: 0.34 ± 0.02, M2: 4.17 ± 0.36 %dose/mg protein). The GST-P1 expression level in M1 macrophages was higher than that in M2 and M0 macrophages [GST-P1/β-actin normalized by M0: 9.0 ± 3.7 (M1), 1.2 ± 0.2 (M2)]. The MRP1 expression level in M1 macrophages was significantly higher than that in M2 and M0 macrophages [MRP1/β-actin normalized by M0 macrophages: 5.1 ± 2.1 (M1), 2.8 ± 1.0 (M2)]. CONCLUSIONS: 18F-FMISO accumulation in macrophages may depend on the polarization state in addition to hypoxic condition.
• [18F]DPA-714 PET imaging shows immunomodulatory effect of intravenous administration of bone marrow stromal cells after transient focal ischemia.

  Chengbo Tan, Songji Zhao, Kei Higashikawa, Zifeng Wang, Masahito Kawabori, Takeo Abumiya, Naoki Nakayama, Ken Kazumata, Naoyuki Ukon, Hironobu Yasui, Nagara Tamaki, Yuji Kuge, Hideo Shichinohe, Kiyohiro Houkin

  EJNMMI research 8 (1) 35 - 35 2018/05/02 [Refereed][Not invited]
   

  BACKGROUND: The potential application of bone marrow stromal cell (BMSC) therapy in stroke has been anticipated due to its immunomodulatory effects. Recently, positron emission tomography (PET) with [18F]DPA-714, a translocator protein (TSPO) ligand, has become available for use as a neural inflammatory indicator. We aimed to evaluate the effects of BMSC administration after transient middle cerebral artery occlusion (MCAO) using [18F]DPA-714 PET. The BMSCs or vehicle were administered intravenously to rat MCAO models at 3 h after the insult. Neurological deficits, body weight, infarct volume, and histology were analyzed. [18F]DPA-714 PET was performed 3 and 10 days after MCAO. RESULTS: Rats had severe neurological deficits and body weight loss after MCAO. Cell administration ameliorated these effects as well as the infarct volume. Although weight loss occurred in the spleen and thymus, cell administration suppressed it. In both vehicle and BMSC groups, [18F]DPA-714 PET showed a high standardized uptake value (SUV) around the ischemic area 3 days after MCAO. Although SUV was increased further 10 days after MCAO in both groups, the increase was inhibited in the BMSC group, significantly. Histological analysis showed that an inflammatory reaction occurred in the lymphoid organs and brain after MCAO, which was suppressed in the BMSC group. CONCLUSIONS: The present results suggest that BMSC therapy could be effective in ischemic stroke due to modulation of systemic inflammatory responses. The [18F]DPA-714 PET/CT system can accurately demonstrate brain inflammation and evaluate the BMSC therapeutic effect in an imaging context. It has great potential for clinical application.
• In vitro uptake and metabolism of [14C]acetate in rabbit atherosclerotic arteries: biological basis for atherosclerosis imaging with [11C]acetate

  Kazuaki Yamasaki, Atsushi Yamashita, Yan Zhao, Yoichi Shimizu, Ryuichi Nishii, Keiichi Kawai, Nagara Tamaki, Songji Zhao, Yujiro Asada, Yuji Kuge

  Nuclear Medicine and Biology 56 21 - 25 1872-9614 2018/01/01 [Refereed][Not invited]
   

  Introduction Detection of vulnerable plaques is critically important for the selection of appropriate treatment and/or the prevention of atherosclerosis and ensuing cardiovascular diseases. In order to clarify the utility of [11C]acetate for atherosclerosis imaging, we determined the uptake and metabolism of acetate by in vitro studies using rabbit atherosclerotic arteries and [14C]acetate. Methods Rabbits were fed with a conventional (n = 5) or a 0.5% cholesterol diet (n = 6). One side of the iliac–femoral arteries was injured by a balloon catheter. Radioactivity levels in the iliac–femoral arteries were measured after incubation in DMEM containing [1-14C]acetate for 60 min (% dpm/mg tissue). Radioactive components in the homogenized arteries were partitioned into aqueous, organic, and residue fractions by the Folch method, and analyzed by thin-layer chromatography (TLC). Results The radioactivity level in the injured arteries of rabbits fed with the 0.5% cholesterol diet (atherosclerotic arteries) was significantly higher than that in either the non-injured or injured arteries of rabbits fed with the conventional diet (p < 0.05) (% dpm/mg tissue: conventional diet groups 0.022 ± 0.005 and 0.024 ± 0.007, cholesterol diet groups 0.029 ± 0.007 and 0.034 ± 0.005 for non-injured and injured arteries). In metabolite analysis, most of the radioactivity was found in the aqueous fraction in each group (87.4–94.6% of total radioactivity in the arteries), and glutamate was a dominant component (67.4–69.7% of the aqueous fraction in the arteries). Conclusions The level of [14C]acetate-derived radioactivity into the arteries was increased by balloon injury and the burden of a cholesterol diet. Water-soluble metabolites were the dominant components with radioactivity in the atherosclerotic lesions. These results provide a biological basis for imaging atherosclerotic lesions by PET using [11C]acetate.
• Measurement of Iodine-Derived Contamination in L-[¹¹C]Methionine Injection

  Komatsu Yukiko, Tamaki Nagara, Kuge Yuji, Nishijima Ken-ichi, Oomagari Shigeo, Kanai Yasukazu, Naka Sadahiro, Higashikawa Kei, Ebita Yoko, Shiga Tohru, Hatazawa Jun

  RADIOISOTOPES 公益社団法人 日本アイソトープ協会 67 (3) 75 - 83 0033-8303 2018 [Refereed][Not invited]
   

  Measurement methods for iodine-derived contamination in L-[¹¹C]methionine injection were evaluated. L-[¹¹C]Methionine injection and samples from the mock synthesis routes where iodine vapor was introduced with or without passing precolumns of sodium hydroxide-coated silica (Ascarite columns) were used. The contents of total iodine, iodide ion, and I₂ were determined by ICP-MS, HPLC-UV detection, and N,N-diethyl-1,4 phenylenediamine method, respectively. Total iodine contents measured by ICP-MS indicated the potentials of Ascarite columns for removing I₂ . The iodine-derived contamination existed as iodide ion in the L-[¹¹C]methionine injections. Accordingly, measurement of iodide ion by HPLC offers a rapid and useful means of controlling the manufacturing processes of L-[¹¹C]methionine injection.

• Anti PD-1 treatment increases [18F]FDG uptake by cancer cells in a mouse B16F10 melanoma model.

  Tomita M, Yasui H, Higashikawa K, Nakajima K, Takakura H, Shiga T, Kuge Y, Ogawa M

  EJNMMI Res 8 (1) 82  2018 [Refereed][Not invited]
  
• Relationship between intelligence quotient (IQ) and cerebral metabolic rate of oxygen in patients with neurobehavioural disability after traumatic brain injury.

  Abiko K, Shiga T, Katoh C, Hirata K, Kuge Y, Kobayashi K, Ikeda S, Ikoma K

  Brain Inj 32 (11) 1367 - 1372 2018 [Refereed][Not invited]
  
• ホットセルに格納可能な小型RIガス貯留装置の開発

  阿保 憲史, 野矢 洋一, 東川 桂, 安井 博宣, 久下 裕司

  日本放射線安全管理学会誌 (一社)日本放射線安全管理学会 16 (2) 85 - 90 1347-1503 2017/11 [Refereed][Not invited]
  
• In-111-DTPA-D-Phe(-1)-Asp(0)-D-Phe(1)-octreotide exhibits higher tumor accumulation and lower renal radioactivity than In-111-DTPA-D-Phe(1)-octreotide

  Nobuhiro Oshima, Hiromichi Akizawa, Hirotake Kitaura, Hidekazu Kawashima, Songji Zhao, Yan Zhao, Ken-ichi Nishijima, Yoji Kitamura, Yasushi Arano, Yuji Kuge, Kazue Ohkura

  NUCLEAR MEDICINE AND BIOLOGY 54 18 - 26 0969-8051 2017/11 [Refereed][Not invited]
   

  Introduction: In-111-DTPA-D-Phe(1)-octreotide scintigraphy is an important method of detecting neuroendocrine tumors. We previously reported that a new derivative of In-111-DTPA-D-Phe(1)-octreotide, In-111-DTPA-D-Phe(-1)-Asp(0)-D-Phe(1)-octreotide, accomplished the reduction of prolonged renal accumulation of radioactivity. The aim of this study was to evaluate the tumor accumulation of In-111-DTPA-D-Phe(-1)-Asp-D-Phe(1)-octreotide in vitro and in vivo by comparing it with In-111-DTPA-D-Phe(1)-octreotide. Methods: The tumor accumulation of this octreotide derivative was determined by measuring its uptake using cultured AR42J cells in vitro and biodistribution studies in vivo. The distribution of the radiotracer and the extent of somatostatin receptor-specific uptake in the tumor were estimated by a counting method using AR42J tumor-bearing mice. The radioactive metabolite species in the tumor and kidney were identified by HPLC analyses at 3 and 24 h post-injection of the In-111-DTPA-conjugated peptide. Results: In both cases, in vitro and in vivo, the tumor radioactivity levels of In-111-DTPA-D-Phe(-1)-Asp-D-Phe-loctreotide were approximately 2-4 times higher than those of In-111-DTPA-D-Phe(1)-octreotide. On in vitro cellular uptake inhibition and radioreceptor assay, In-111-DTPA-D-Phe(-1)-Asp-D-Phe(1)-octreotide exhibited a binding affinity to somatostatin receptor highly similar to that of In-111-DTPA-D-Phe(1)-octreotide. As the additional cellular uptake of In-111-DTPA-D-Phe(-1)-Asp-D-Phe(1)-octreotide was significantly lower at low temperature than at 37 degrees C, it was considered that a cellular uptake pathway is involved in energy-dependent endocytotic processes. In the radiometabolite analysis of In-111-DTPA-D-Phe(-1)-Asp-D-Phe(1)-octreotide, In-111-DTPA-D-Phe-Asp-OH was a major metabolite in the tumor at 24 h post-injection. Conclusion: In-111-DTPA-D-Phe(-1)-Asp-D-Phe(1)-octreotide exhibited higher tumor accumulation and persistence of tumor radioactivity than In-111-DTPA-D-Phe(1)-octreotide. We reasoned that this higher tumor accumulation would not be based on the receptor affinity but on a receptor-mediated endocytotic process involved in temperature-dependent cellular uptake. The present study demonstrated the great potential of the pharmaceutical development of a new radiolabeled peptide with high tumor accumulation and low renal radioactivity by the chemical modification of In-111-DTPA-D-Phe(1)-octreotide. (C) 2017 Elsevier Inc. All rights reserved.
• FMISO accumulation in tumor is dependent on glutathione conjugation capacity in addition to hypoxic state

  Yukiko Masaki, Yoichi Shimizu, Takeshi Yoshioka, Ken-ichi Nishijima, Songji Zhao, Kenichi Higashino, Yoshito Numata, Nagara Tamaki, Yuji Kuge

  ANNALS OF NUCLEAR MEDICINE 31 (8) 596 - 604 0914-7187 2017/10 [Refereed][Not invited]
   

  Objective F-18-fluoromisonidazole (FMISO), a well-known PET imaging probe for diagnosis of hypoxia, is believed to accumulate in hypoxic cells via covalent binding with macromolecules after reduction of the nitro group. Previously, we showed the majority of F-18-FMISO was incorporated into low-molecular-weight metabolites in hypoxic tumors, and the glutathione conjugate of reduced FMISO (amino-FMISO-GS) distributed in the tumor hypoxic regions as revealed by imaging mass spectrometry (IMS). The present study was conducted to clarify whether FMISO is metabolized to amino-FMISO-GS within tumor cells and how amino-FMISO-GS contributes to FMISO accumulation in hypoxic cells. We also evaluated the relationship between FMISO accumulation and the glutathione conjugation-related factors in the cells. Methods Tumor cells (FaDu, LOVO, and T24) were treated with F-18-FMISO and incubated under normoxic or hypoxic conditions for 4 h. The FMISO metabolites were analyzed with LC-ESI-MS. Several glutathione conjugation-related factors of tumor cells were evaluated in vitro. FaDu tumor-bearing mice were intravenously injected with F-18-FMISO and the tumors were excised at 4 h post-injection. Autoradiography, IMS and histologic studies were performed. Results Amino-FMISO-GS was the main contributor to FMISO incorporated in hypoxic FaDu cells in vitro and in vivo. Total FMISO uptake levels and amino-FMISO-GS levels were highest in FaDu, followed by LOVO, and then T24 (total uptake: 0.851 +/- 0.009 (FaDu), 0.617 +/- 0.021 (LOVO) and 0.167 +/- 0.006 (T24) % dose/mg protein; amino-FMISO-GS: 0.502 +/- 0.035 (FaDu), 0.158 +/- 0.013 (LOVO), and 0.007 +/- 0.001 (T24) % dose/mg protein). The glutathione level of FaDu was significantly higher than those of LOVO and T24. The enzyme activity of glutathione-S-transferase catalyzing the glutathione conjugation reaction in FaDu was similar levels to that in LOVO, and was higher than that in T24. Quantitative RT-PCR analysis revealed that the expression levels of efflux transporters of the glutathione conjugate (multidrug resistance-associated protein 1) were lowest in FaDu, followed by LOVO, and then T24. Conclusions FMISO accumulates in hypoxic cells through reductive metabolism followed by glutathione conjugation. We illustrated the possibility that increased production and decreased excretion of amino-FMISO-GS contribute to FMISO accumulation in tumor cells under hypoxic conditions.
• F-18-Fluoromisonidazole positron emission tomography (FMISO-PET) may reflect hypoxia and cell proliferation activity in oral squamous cell carcinoma

  Jun Sato, Yoshimasa Kitagawa, Shiro Watanabe, Takuya Asaka, Noritaka Ohga, Kenji Hirata, Shozo Okamoto, Tohru Shiga, Masanobu Shindoh, Yuji Kuge, Nagara Tamaki

  ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY ORAL RADIOLOGY 124 (3) 261 - 270 2212-4403 2017/09 [Refereed][Not invited]
   

  Objective. Hypoxia is a common feature and prognostic factor in cancer. F-18-fluoromisonidazole (FMISO) positron emission tomography (PET) can detect tumor hypoxia noninvasively. The aim of this study was to assess the correlations between FMISO-PET and F-18-fluorodexyglucose (FDG)-PET parameters with cell proliferation and hypoxia in patients with oral squamous cell carcinoma (OSCC). Study Design. Twenty-three preoperative patients with OSCC were included. The tumor/muscle ratio (TMR) of FMISO-PET, the maximum standardized uptake values (SUVmax) of FDG-PET, metabolic tumor volume, and total lesion glycolysis were measured. Ki-67 and hypoxia-inducible factor-1 alpha (HIF-1 alpha) expression was immunohistochemically evaluated. Results. FMISO TMR (P = .003) and FDG SUVmax (P = .04) were significantly higher in patients with high expression of Ki-67 compared with those with low expression of Ki-67. FMISO TMR (P = .006) and FDG SUVmax (P = .01) were also significantly higher in patients with HIF-1 alpha expression than in those without HIF-1 alpha expression. Metabolic tumor volume was not significantly related to either Ki-67 or HIF-1 alpha expression. Multivariate analysis showed that FMISO TMR was independently predictive of Ki-67 (P = .002; odds ratio 31.1) and HIF-1 alpha (P = .049; odds ratio 10.5) expression. Conclusions. FMISO-PET showed significant relationships with Ki-67 and HIF-1 alpha expression, which are key features of cell proliferation and hypoxia in OSCC.
• Local relapse of nasopharyngeal cancer and Voxel-based analysis of FMISO uptake using PET with semiconductor detectors

  Yukiko Nishikawa, Koichi Yasuda, Shozo Okamoto, Yoichi M. Ito, Rikiya Onimaru, Tohru Shiga, Kazuhiko Tsuchiya, Shiro Watanabe, Wataru Takeuchi, Yuji Kuge, Hao Peng, Nagara Tamaki, Hiroki Shirato

  RADIATION ONCOLOGY 12 148  1748-717X 2017/09 [Refereed][Not invited]
   

  Background: Hypoxic cancer cells are thought to be radioresistant and could impact local recurrence after radiotherapy (RT). One of the major hypoxic imaging modalities is [F-18] fluoromisonidazole positron emission tomography (FMISO-PET). High FMISO uptake before RT could indicate radioresistant sites and might be associated with future local recurrence. The predictive value of FMISO-PET for intra-tumoral recurrence regions was evaluated using high-resolution semiconductor detectors in patients with nasopharyngeal carcinoma after intensity-modulated radiotherapy (IMRT). Methods: Nine patients with local recurrence and 12 patients without local recurrence for more than 3 years were included in this study. These patients received homogeneous and standard doses of radiation to the primary tumor irrespective of FMISO uptake. The FMISO-PET image before RT was examined via a voxel-based analysis, which focused on the relationship between the degree of FMISO uptake and recurrence region. Results: In the pretreatment FMISO-PET images, the tumor-to-muscle ratio (TMR) of FMISO in the voxels of the tumor recurrence region was significantly higher than that of the non-recurrence region (p < 0.0001). In the recurrent patient group, a TMR value of 1.37 (95% CI: 1.36-1.39) corresponded to a recurrence rate of 30%, the odds ratio was 5.18 (4.87-5.51), and the area under the curve (AUC) of the receiver operating characteristic curve was 0.613. In all 21 patients, a TMR value of 2.42 (2.36-2.49) corresponded to an estimated recurrence rate of 30%, and the AUC was only 0.591. Conclusions: The uptake of FMISO in the recurrent region was significantly higher than that in the non-recurrent region. However, the predictive value of FMISO-PET before IMRT is not sufficient for up-front dose escalation for the intra-tumoral high-uptake region of FMISO. Because of the higher mean TMR of the recurrence region, a new hypoxic imaging method is needed to improve the sensitivity and specificity for hypoxia.
• Changes in tumor oxygen state after sorafenib therapy evaluated by F-18-fluoromisonidazole hypoxia imaging of renal cell carcinoma xenografts

  Wenwen Yu, Songji Zhao, Yan Zhao, Chowdhury Nusrat Fatema, Masahiro Murakami, Ken-Ichi Nishijima, Yoshimasa Kitagawa, Nagara Tamaki, Yuji Kuge

  ONCOLOGY LETTERS 14 (2) 2341 - 2346 1792-1074 2017/08 [Refereed][Not invited]
   

  A mechanistic dissociation exists between tumor starvation and vascular normalization after antiangiogenic therapy. Thus, improved understanding of tumor responses (tumor starvation or vascular normalization) is important for optimizing treatment strategies. F-18-fluoromisonidazole (F-18-FMISO) is widely used for imaging tumor hypoxia. To clarify the tumor response to the antiangiogenic drug sorafenib, the present study evaluated the changes in the tumor oxygen state using F-18-FMISO in mice bearing a renal cell carcinoma xenograft (A498). Mice bearing A498 xenografts were assigned to the control and three sorafenib-treatment groups and administered sorafenib (0, 10, 20 or 40 mg/kg/day, per os) once daily for 3 days. Following one day after the final administration, the mice were injected with F-18-FMISO and pimonidazole (a hypoxia marker). F-18-FMISO accumulation in the tumor was determined by autoradiography. Immunohistochemistry of pimonidazole and cluster of differentiation (CD) 31 (a vascular marker) was also performed. F-18-FMISO accumulation levels in the tumor significantly increased by 4.3-, 8.4- and 8.6-fold compared with in the control group following 10, 20 and 40 mg/kg sorafenib treatments, respectively [0.07 +/- 0.04, 0.32 +/- 0.11, 0.62 +/- 0.15 and 0.63 +/- 0.23 (% ID/m(2)) x kg for the control, and 10, 20 and 40 mg treatments, respectively; all P<0.0083 vs. the control]. The number of pimonidazole-positive cells also significantly increased by 6.8-, 12.3-and 20.2-fold compared with in the control group following 10, 20 and 40 mg/kg sorafenib treatments, respectively (0.78 +/- 0.79, 5.36 +/- 2.29, 9.66 +/- 1.58 and 15.85 +/- 4.59% pimonidazole-positive cells; all P<0.0083 vs. the control). The number of microvessels in tumors markedly decreased to 33.5, 17.6, and 14.0% of the control following 10, 20 and 40 mg/kg sorafenib treatments, respectively (17.1 +/- 2.5, 5.7 +/- 1.0, 3.0 +/- 1.0 and 2.4 +/- 0.3 vessels/mm(2); P<0.0083 vs. the control). The F-18-FMISO expression level in the tumor increased sorafenib-dose-dependently, which is consistent with the increase in the number of pimonidazole-positive cells and decrease in the number of microvessels. These findings indicated that the present sorafenib treatment protocol induces 'tumor hypoxia/starvation' in the renal cell carcinoma xenograft (A498) due to its antiangiogenic properties.
• Immunoglobulin G (IgG)-Based Imaging Probe Accumulates in M1 Macrophage-Infiltrated Atherosclerotic Plaques Independent of IgG Target Molecule Expression

  Yoichi Shimizu, Hiroko Hanzawa, Yan Zhao, Sagiri Fukura, Ken-ichi Nishijima, Takeshi Sakamoto, Songji Zhao, Nagara Tamaki, Mikako Ogawa, Yuji Kuge

  MOLECULAR IMAGING AND BIOLOGY 19 (4) 531 - 539 1536-1632 2017/08 [Refereed][Not invited]
   

  Vulnerable plaques are key factors for ischemic diseases. Thus, their precise detection is necessary for the diagnosis of such diseases. Immunoglobulin G (IgG)-based imaging probes have been developed for imaging biomolecules related to plaque formation for the diagnosis of atherosclerosis. However, IgG accumulates nonspecifically in atherosclerotic regions, and its accumulation mechanisms have not yet been clarified in detail. Therefore, we explored IgG accumulation mechanisms in atherosclerotic lesions and examined images of radiolabeled IgG for the diagnosis of atherosclerosis. Mouse IgG without specificity to biomolecules was labeled with technetium-99m via 6-hydrazinonicotinate to yield [Tc-99m]IgG. ApoE(-/-) or C57BL/6J mice were injected intravenously with [Tc-99m]IgG, and their aortas were excised 24 h after injection. After radioactivity measurement, serial aortic sections were autoradiographically and histopathologically examined. RAW264.7 macrophages were polarized into M1 or M2 and then treated with [Tc-99m]IgG. The radioactivities in the cells were measured after 1 h of incubation. [Tc-99m]IgG uptake in M1 macrophages was also evaluated after the pretreatment with an anti-Fc gamma receptor (Fc gamma R) antibody. The expression levels of Fc gamma Rs in the cells were measured by western blot analysis. [Tc-99m]IgG accumulation levels in the aortas were significantly higher in apoE(-/-) mice than in C57BL/6J mice (5.1 +/- A 1.4 vs 2.8 +/- A 0.5 %ID/g, p < 0.05). Autoradiographic images showed that the accumulation areas highly correlated with the macrophage-infiltrated areas. M1 macrophages showed significantly higher levels of [Tc-99m]IgG than M2 or M0 (nonpolarized) macrophages [2.2 +/- A 0.3 (M1) vs 0.5 +/- A 0.1 (M2), 0.4 +/- A 0.1 (M0) %dose/mg protein, p < 0.01] and higher expression levels of Fc gamma RI and Fc gamma RII. [Tc-99m]IgG accumulation in M1 macrophages was suppressed by pretreatment with the anti-Fc gamma R antibody [2.2 +/- A 0.3 (nonpretreatment) vs 1.2 +/- A 0.2 (pretreatment) %ID/mg protein, p < 0.01]. IgG accumulated in pro-inflammatory M1 macrophages via Fc gamma Rs in atherosclerotic lesions. Thus, the target biomolecule-independent imaging of active inflammation should be taken into account in the diagnosis of atherosclerosis using IgG-based probes.
• Redesign of negatively charged In-111-DTPA-octreotide derivative to reduce renal radioactivity

  Nobuhiro Oshima, Hiromichi Akizawa, Hidekazu Kawashima, Songji Zhao, Yan Zhao, Ken-ichi Nishijima, Yoji Kitamura, Yasushi Arano, Yuji Kuge, Kazue Ohkura

  NUCLEAR MEDICINE AND BIOLOGY 48 16 - 25 0969-8051 2017/05 [Refereed][Not invited]
   

  Introduction: Radiolabeled octreotide derivatives have been studied as diagnostic and therapeutic agents for somatostatin receptor-positive tumors. To prevent unnecessary radiation exposure during their clinical application, the present study aimed to develop radiolabeled peptides which could reduce radioactivity levels in the kidney at both early and late post-injection time points by introducing a negative charge with an acidic amino acid such as L-aspartic acid (Asp) at a suitable position in In-111-DTPA-conjugated octreotide derivatives. Methods: Biodistribution of the radioactivity was evaluated in normal mice after administration of a novel radiolabeled peptide by a counting method. The radiolabeled species remaining in the kidney were identified by comparing their HPLC data with those obtained by alternative synthesis. Results: The designed and synthesized radiolabeled peptide In-111-DTPA-D-Phe(-1)-Aspo(o)-D-phe(1)-octreotide exhibited significantly lower renal radioactivity levels than those of the known In-111-DTPA-D-Phe(-1)-octreotide at 3 and 24 h post-injection. The radiolabeled species in the kidney at 24 h after the injection of new octreotide derivative represented In-111-DTPA-D-Phe-OH and In-111-DTPA-D-Phe-Asp-OH as the metabolites. Their radiometabolites and intact In-111-DTPA-conjugated octreotide derivative were observed in urine within 24 h post-injection. Conclusion: The present study provided a new example of an In-111-DTPA-conjugated octreotide derivative having the characteristics of both reduced renal uptake and shortened residence time of radioactivity in the kidney. It is considered that this kinetic control was achieved by introducing a negative charge on the octreotide derivative thereby suppressing the reabsorption in the renal tubules and affording the radiometabolites with appropriate lipophilicity. (C) 2017 Elsevier Inc. All rights reserved.
• Hypoxic glucose metabolism in glioblastoma as a potential prognostic factor.

  Takuya Toyonaga, Shigeru Yamaguchi, Kenji Hirata, Kentaro Kobayashi, Osamu Manabe, Shiro Watanabe, Shunsuke Terasaka, Hiroyuki Kobayashi, Naoya Hattori, Tohru Shiga, Yuji Kuge, Shinya Tanaka, Yoichi M Ito, Nagara Tamaki

  European journal of nuclear medicine and molecular imaging 44 (4) 611 - 619 2017/04 [Refereed][Not invited]
   

  PURPOSE: Metabolic activity and hypoxia are both important factors characterizing tumor aggressiveness. Here, we used F-18 fluoromisonidazole (FMISO) and F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) to define metabolically active hypoxic volume, and investigate its clinical significance in relation to progression free survival (PFS) and overall survival (OS) in glioblastoma patients. EXPERIMENTAL DESIGN: Glioblastoma patients (n = 32) underwent FMISO PET, FDG PET, and magnetic resonance imaging (MRI) before surgical intervention. FDG and FMISO PET images were coregistered with gadolinium-enhanced T1-weighted MR images. Volume of interest (VOI) of gross tumor volume (GTV) was manually created to enclose the entire gadolinium-positive areas. The FMISO tumor-to-normal region ratio (TNR) and FDG TNR were calculated in a voxel-by-voxel manner. For calculating TNR, standardized uptake value (SUV) was divided by averaged SUV of normal references. Contralateral frontal and parietal cortices were used as the reference region for FDG, whereas the cerebellar cortex was used as the reference region for FMISO. FDG-positive was defined as the FDG TNR ≥1.0, and FMISO-positive was defined as FMISO TNR ≥1.3. Hypoxia volume (HV) was defined as the volume of FMISO-positive and metabolic tumor volume in hypoxia (hMTV) was the volume of FMISO/FDG double-positive. The total lesion glycolysis in hypoxia (hTLG) was hMTV × FDG SUVmean. The extent of resection (EOR) involving cytoreduction surgery was volumetric change based on planimetry methods using MRI. These factors were tested for correlation with patient prognosis. RESULTS: All tumor lesions were FMISO-positive and FDG-positive. Univariate analysis indicated that hMTV, hTLG, and EOR were significantly correlated with PFS (p = 0.007, p = 0.04, and p = 0.01, respectively) and that hMTV, hTLG, and EOR were also significantly correlated with OS (p = 0.0028, p = 0.037, and p = 0.014, respectively). In contrast, none of FDG TNR, FMISO TNR, GTV, HV, patients' age, or Karnofsky performance scale (KPS) was significantly correlated with PSF or OS. The hMTV and hTLG were found to be independent factors affecting PFS and OS on multivariate analysis. CONCLUSIONS: We introduced hMTV and hTLG using FDG and FMISO PET to define metabolically active hypoxic volume. Univariate and multivariate analyses demonstrated that both hMTV and hTLG are significant predictors for PFS and OS in glioblastoma patients.
• Altered glucose metabolism and hypoxic response in alloxan-induced diabetic atherosclerosis in rabbits

  Yunosuke Matsuura, Atsushi Yamashita, Yan Zhao, Takashi Iwakiri, Kazuaki Yamasaki, Chihiro Sugita, Chihiro Koshimoto, Kazuo Kitamura, Keiichi Kawai, Nagara Tamaki, Songji Zhao, Yuji Kuge, Yujiro Asada

  PLOS ONE 12 (4) e0175976  1932-6203 2017/04 [Refereed][Not invited]
   

  Diabetes mellitus accelerates atherosclerosis that causes most cardiovascular events. Several metabolic pathways are considered to contribute to the development of atherosclerosis, but comprehensive metabolic alterations to atherosclerotic arterial cells remain unknown. The present study investigated metabolic changes and their relationship to vascular histopathological changes in the atherosclerotic arteries of rabbits with alloxan-induced diabetes. Diabetic atherosclerosis was induced in rabbit ilio-femoral arteries by injecting alloxan ( 100 mg/kg), injuring the arteries using a balloon, and feeding with a 0.5% cholesterol diet. We histologically assessed the atherosclerotic lesion development, cellular content, pimonidazole positive-hypoxic area, the nuclear localization of hypoxia-inducible factor-1 alpha, and apoptosis. We evaluated comprehensive arterial metabolism by performing metabolomic analyses using capillary electrophoresis-time of flight mass spectrometry. We evaluated glucose uptake and its relationship to vascular hypoxia using 18 F-fluorodeoxyglucose and pimonidazole. Plaque burden, macrophage content, and hypoxic areas were more prevalent in arteries with diabetic, than non-diabetic atherosclerosis. Metabolomic analyses highlighted 12 metabolites that were significantly altered between diabetic and non-diabetic atherosclerosis. A half of them were associated with glycolysis metabolites, and their levels were decreased in diabetic atherosclerosis. The uptake of glucose evaluated as 18 F-fluorodeoxyglucose in atherosclerotic lesions increased according to increased macrophage content or hypoxic areas in non-diabetic, but not diabetic rabbits. Despite profound hypoxic areas, the nuclear localization of hypoxia- inducible factor-1a decreased and the number of apoptotic cells increased in diabetic atherosclerotic lesions. Altered glycolysis metabolism and an impaired response to hypoxia in atherosclerotic lesions under conditions of insulin-dependent diabetes might be involved in the development of diabetic atherosclerosis.
• I-123 iomazenil single photon emission computed tomography for detecting loss of neuronal integrity in patients with traumatic brain injury

  Kagari Abiko, Katsunori Ikoma, Tohru Shiga, Chietsugu Katoh, Kenji Hirata, Yuji Kuge, Kentaro Kobayashi, Nagara Tamaki

  EJNMMI RESEARCH 7 (1) 28  2191-219X 2017/03 [Refereed][Not invited]
   

  Background: Traumatic brain injury (TBI) causes brain dysfunction in many patients. Using C-11 flumazenil (FMZ) positron emission tomography (PET), we have detected and reported the loss of neuronal integrity, leading to brain dysfunction in TBI patients. Similarly to FMZ PET, I-123 iomazenil (IMZ) single photon emission computed tomography (SPECT) is widely used to determine the distribution of the benzodiazepine receptor (BZR) in the brain cortex. The purpose of this study is to examine whether IMZ SPECT is as useful as FMZ PET for evaluating the loss of neuronal integrity in TBI patients. The subjects of this study were seven patients who suffered from neurobehavioral disability. They underwent IMZ SPECT and FMZ PET. Nondisplaceable binding potential (BPND) was calculated from FMZ PET images. The uptake of IMZ was evaluated on the basis of lesion-to-pons ratio (LPR). The locations of low uptake levels were visually evaluated both in IMZ SPECT and FMZ PET images. We compared FMZ BPND and (LPR-1) of IMZ SPECT. Results: In the visual assessment, FMZ BPND decreased in 11 regions. In IMZ SPECT, low uptake levels were observed in eight of the 11 regions. The rate of concordance between FMZ PET and IMZ SPECT was 72.7%. The mean values IMZ (LPR-1) (1.95 +/- 1.01) was significantly lower than that of FMZ BPND (2.95 +/- 0.80 mL/mL). There was good correlation between FMZ BPND and IMZ (LPR-1) (r = 0.80). Conclusions: IMZ SPECT findings were almost the same as FMZ PET findings in TBI patients. The results indicated that IMZ SPECT is useful for evaluating the loss of neuronal integrity. Because IMZ SPECT can be performed in various facilities, IMZ SPECT may become widely adopted for evaluating the loss of neuronal integrity.
• Dynamic PET evaluation of elevated FLT level after sorafenib treatment in mice bearing human renal cell carcinoma xenograft

  Naoyuki Ukon, Songji Zhao, Wenwen Yu, Yoichi Shimizu, Ken-ichi Nishijima, Naoki Kubo, Yoshimasa Kitagawa, Nagara Tamaki, Kei Higashikawa, Hironobu Yasui, Yuji Kuge

  EJNMMI RESEARCH 6 (1) 90  2191-219X 2016/12 [Refereed][Not invited]
   

  Background: Sorafenib, an oral multikinase inhibitor, has anti-proliferative and anti-angiogenic activities and is therapeutically effective against renal cell carcinoma (RCC). Recently, we have evaluated the tumor responses to sorafenib treatment in a RCC xenograft using [Methyl-H-3(N)]-3'-fluoro-3'-deoxythythymidine ([H-3]FLT). Contrary to our expectation, the FLT level in the tumor significantly increased after the treatment. In this study, to clarify the reason for the elevated FLT level, dynamic 3'-[F-18]fluoro-3'-deoxythymidine ([F-18] FLT) positron emission tomography (PET) and kinetic studies were performed in mice bearing a RCC xenograft (A498). The A498 xenograft was established in nude mice, and the mice were assigned to the control (n = 5) and treatment (n = 5) groups. The mice in the treatment group were orally given sorafenib (20 mg/kg/day p.o.) once daily for 3 days. Twenty-four hours after the treatment, dynamic [F-18] FLT PET was performed by small-animal PET. Three-dimensional regions of interest (ROIs) were manually defined for the tumors. A three-compartment model fitting was carried out to estimate four rate constants using the time activity curve (TAC) in the tumor and the blood clearance rate of [F-18] FLT. Results: The dynamic pattern of [F-18] FLT levels in the tumor significantly changed after the treatment. The rate constant of [F-18] FLT phosphorylation (k(3)) was significantly higher in the treatment group (0.111 +/- 0.027 [1/min]) than in the control group (0.082 +/- 0.009 [1/min]). No significant changes were observed in the distribution volume, the ratio of [F-18] FLT forward transport (K-1) to reverse transport (k(2)), between the two groups (0.556 +/- 0.073 and 0. 641 +/- 0.052 [mL/g] in the control group). Conclusions: Our dynamic PET studies indicated that the increase in FLT level may be caused by the phosphorylation of FLT in the tumor after the sorafenib treatment in the mice bearing a RCC xenograft. Dynamic PET studies with kinetic modeling could provide improved understanding of the biochemical processes involved in tumor responses to therapy.
• The reoxygenation of hypoxia and the reduction of glucose metabolism in head and neck cancer by fractionated radiotherapy with intensity-modulated radiation therapy

  Shozo Okamoto, Tohru Shiga, Koichi Yasuda, Shiro Watanabe, Kenji Hirata, Ken-ichi Nishijima, Keiichi Magota, Katsuhiko Kasai, Rikiya Onimaru, Kazuhiko Tuchiya, Yuji Kuge, Hiroki Shirato, Nagara Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 43 (12) 2147 - 2154 1619-7070 2016/11 [Refereed][Not invited]
   

  The purpose of this study was to prospectively investigate reoxygenation in the early phase of fractionated radiotherapy and serial changes of tumoricidal effects associated with intensity-modulated radiation therapy (IMRT) in patients with head and neck cancer (HNC) using F-18 fluoromisonidazole (FMISO) PET and F-18 fluorodeoxyglucose (FDG) PET. Patients with untreated HNC underwent FMISO-PET and FDG-PET studies prospectively. A PET evaluation was conducted before each IMRT (Pre-IMRT), during IMRT (at 30 Gy/15 fr) (Inter-IMRT), and after completion of IMRT (70 Gy/35 fr) (Post-IMRT). FMISO-PET images were scanned by a PET/CT scanner at 4 h after the FMISO injection. We quantitatively analyzed the FMISO-PET images of the primary lesion using the maximum standardized uptake (SUVmax) and tumor-to-muscle ratio (TMR). The hypoxic volume (HV) was calculated as an index of tumor hypoxia, and was defined as the volume when the TMR was aeyen 1.25. Each FDG-PET scan was started 1 h after injection. The SUVmax and metabolic tumor volume (MTV) values obtained by FDG-PET were analyzed. Twenty patients finished the complete PET study protocol. At Pre-IMRT, 19 patients had tumor hypoxia in the primary tumor. In ten patients, the tumor hypoxia disappeared at Inter-IMRT. Another seven patients showed the disappearance of tumor hypoxia at Post-IMRT. Two patients showed tumor hypoxia at Post-IMRT. The FMISO-PET results showed that the reduction rates of both SUVmax and TMR from Pre-IMRT to Inter-IMRT were significantly higher than the corresponding reductions from Inter-IMRT to Post-IMRT (SUVmax: 27 % vs. 10 %, p = 0.025; TMR: 26 % vs. 12 %, p = 0.048). The reduction rate of SUVmax in FDG-PET from Pre-IMRT to Inter-IMRT was similar to that from Inter-IMRT to Post-IMRT (47 % vs. 48 %, p = 0.778). The reduction rate of the HV in FMISO-PET from Pre-IMRT to Inter-IMRT tended to be larger than that from Inter-IMRT to Post-IMRT (63 % vs. 40 %, p = 0.490). Conversely, the reduction rate of the MTV in FDG-PET from Pre-IMRT to Inter-IMRT was lower than that from Inter-IMRT to Post-IMRT (47 % vs. 74 %, p = 0.003). Both the intensity and the volume of tumor hypoxia rapidly decreased in the early phase of radiotherapy, indicating reoxygenation of the tumor hypoxia. In contrast, the FDG uptake declined gradually with the course of radiotherapy, indicating that the tumoricidal effect continues over the entire course of radiation treatment.
• Imaging Mass Spectrometry Revealed the Accumulation Characteristics of the 2-Nitroimidazole-Based Agent "Pimonidazole" in Hypoxia

  Yukiko Masaki, Yoichi Shimizu, Takeshi Yoshioka, Fei Feng, Songji Zhao, Kenichi Higashino, Yoshito Numata, Yuji Kuge

  PLOS ONE 11 (8) e0161639  1932-6203 2016/08 [Refereed][Not invited]
   

  Hypoxia, or low oxygen concentration, is a key factor promoting tumor progression and angiogenesis and resistance of cancer to radiotherapy and chemotherapy. 2-Nitroimidazole- based agents have been widely used in pathological and nuclear medicine examinations to detect hypoxic regions in tumors; in particular, pimonidazole is used for histochemical staining of hypoxic regions. It is considered to accumulate in hypoxic cells via covalent binding with macromolecules or by forming reductive metabolites after reduction of its nitro group. However, the detailed mechanism of its accumulation remains unknown. In this study, we investigated the accumulation mechanism of pimonidazole in hypoxic tumor tissues in a mouse model by mass spectrometric analyses including imaging mass spectrometry (IMS). Pimonidazole and its reductive metabolites were observed in the tumor tissues. However, their locations in the tumor sections were not similar to the positively stained areas in pimonidazole-immunohistochemistry, an area considered hypoxic. The glutathione conjugate of reduced pimonidazole, a low-molecular-weight metabolite of pimonidazole, was found in tumor tissues by LC-MS analysis, and our IMS study determined that the intratumor localization of the glutathione conjugate was consistent with the area positively immunostained for pimonidazole. We also found complementary localization of the glutathione conjugate and reduced glutathione (GSH), implying that formation of the glutathione conjugate occurred in the tumor tissue. These results suggest that in hypoxic tumor cells, pimonidazole is reduced at its nitro group, followed by conjugation with GSH.
• The Thymidine Phosphorylase Imaging Agent I-123-IIMU Predicts the Efficacy of Capecitabine

  Nobuya Kobashi, Hiroki Matsumoto, Songji Zhao, Shunsuke Meike, Yuki Okumura, Tsutomu Abe, Hiromichi Akizawa, Kazue Ohkura, Ken-ichi Nishijima, Nagara Tamaki, Yuji Kuge

  JOURNAL OF NUCLEAR MEDICINE 57 (8) 1276 - 1281 0161-5505 2016/08 [Refereed][Not invited]
   

  Recently, companion diagnostics with nuclear medicine techniques have been anticipated as more suitable means than biopsy for predicting treatment efficacy. The anticancer effect of capecitabine, an orally administered chemotherapeutic agent activated by thymidine phosphorylase (TP), is positively associated with tumor TP expression levels. This study aimed to assess whether TP imaging using a radiolabeled uracil derivative, I-123-5-iodo-6-[(2-iminoimidazolidinyl) methyl] uracil (I-123-IIMU), could predict the efficacy of capecitabine treatment. Methods: Sensitivity to doxifluridine, a metabolite of capecitabine and direct substrate for TP, was assessed by water-soluble tetrazolium salt assays in vitro for 3 human colon cancer cell lines with different TP expression profiles. The intracellular uptake and retention of I-123-IIMU were evaluated. Mice inoculated with each cell line were treated with capecitabine for 2 wk, and tumor growth was compared. In vivo distribution studies and SPECT/CT imaging of I-123-IIMU were performed in inoculated mice. Results: In vitro experiments showed a positive relation between TP expression levels and doxifluridine sensitivity. In vitro studies revealed that intracellular uptake and retention of I-123-IIMU were dependent on TP expression levels. In vivo experiments in inoculated mice showed that I-123-IIMU accumulation in tumor tissue was in line with TP expression levels and susceptibility to capecitabine treatment. Moreover, SPECT/CT imaging of I-123-IIMU in tumor-inoculated mice showed that I-123-IIMU reflects TP expression levels in tumor tissues. Conclusion: I-123-IIMU could be used as an in vivo companion diagnostic for predicting the efficacy of capecitabine treatment.
• Characterization of the role of sphingomyelin synthase 2 in glucose metabolism in whole-body and peripheral tissues in mice

  Masayuki Sugimoto, Yoichi Shimizu, Songji Zhao, Naoyuki Ukon, Ken-ichi Nishijima, Masato Wakabayashi, Takeshi Yoshioka, Kenichi Higashino, Yoshito Numata, Tomohiko Okuda, Nagara Tamaki, Hisatoshi Hanamatsu, Yasuyuki Igarashi, Yuji Kuge

  BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR AND CELL BIOLOGY OF LIPIDS 1861 (8) 688 - 702 1388-1981 2016/08 [Refereed][Not invited]
   

  Sphingomyelin synthase 2 (SMS2) is a proposed potential therapeutic target for obesity and insulin resistance. However, the contributions of SMS2 to glucose metabolism in tissues and its possible therapeutic mechanisms remain unclear. Thus, to determine whole-body glucose utilization and the contributions of each insulin-targeted tissue to glucose uptake, we performed a glucose kinetics study, using the radiolabeled glucose analog F-18-2-fluoro-2-deoxy-D-glucose (F-18-FDG), in wild-type (WT) and SMS2 knockout (KO) mice. Insulin signaling was enhanced in the liver, white adipose tissue and skeletal muscle of SMS2 KO mice compared with those of WT mice. In addition, compared with in WT mice, blood clearance of F-18-FDG was accelerated in SMS2 KO mice when they were fed either a normal or a high fat diet. F-18-FDG uptake was also increased in insulin-targeted tissues such as skeletal muscle in the SMS2 KO mice. Whereas skeletal muscle sphingolipid content was not clearly affected, plasma levels of very long-chain fatty acid (VLCFA)-containing ceramides were markedly increased in SMS2 KO mice, compared with in WT mice. We also generated liver-conditional SMS2 KO mice and performed glucose and insulin tolerance tests on mice with a high fat diet. However, no significant effect was observed. Thus, our study provided evidence that genetic inhibition of SMS2 elevated glucose clearance through activation of glucose uptake into insulin-targeted tissues such as skeletal muscle by a mechanism independent of hepatic SMS2. Our findings further indicate that this occurs, at least in part, via indirect mechanisms such as elevation of VLCFA-containing ceramides. (C) 2016 Elsevier B.V. All rights reserved.
• Continuous-Flow Synthesis of N-Succinimidyl 4-[F-18]fluorobenzoate Using a Single Microfluidic Chip

  Hiroyuki Kimura, Kenji Tomatsu, Hidekazu Saiki, Kenji Arimitsu, Masahiro Ono, Hidekazu Kawashima, Ren Iwata, Hiroaki Nakanishi, Eiichi Ozeki, Yuji Kuge, Hideo Saji

  PLOS ONE 11 (7) e0159303  1932-6203 2016/07 [Refereed][Not invited]
   

  In the field of positron emission tomography ( PET) radiochemistry, compact microreactors provide reliable and reproducible synthesis methods that reduce the use of expensive precursors for radiolabeling and make effective use of the limited space in a hot cell. To develop more compact microreactors for radiosynthesis of F-18-labeled compounds required for the multistep procedure, we attempted radiosynthesis of N-succinimidyl 4-[F-18]fluorobenzoate ([F-18]SFB) via a three-step procedure using a microreactor. We examined individual steps for [F-18]SFB using a batch reactor and microreactor and developed a new continuous-flow synthetic method with a single microfluidic chip to achieve rapid and efficient radiosynthesis of [F-18]SFB. In the synthesis of [F-18]SFB using this continuous-flow method, the three-step reaction was successfully completed within 6.5 min and the radiochemical yield was 64 +/- 2% (n = 5). In addition, it was shown that the quality of [F-18]SFB synthesized on this method was equal to that synthesized by conventional methods using a batch reactor in the radiolabeling of bovine serum albumin with [F-18]SFB.
• (18)F-fluoromisonidazole positron emission tomography can predict pathological necrosis of brain tumors.

  Takuya Toyonaga, Kenji Hirata, Shigeru Yamaguchi, Kanako C Hatanaka, Sayaka Yuzawa, Osamu Manabe, Kentaro Kobayashi, Shiro Watanabe, Tohru Shiga, Shunsuke Terasaka, Hiroyuki Kobayashi, Yuji Kuge, Nagara Tamaki

  European journal of nuclear medicine and molecular imaging 43 (8) 1469 - 76 2016/07 [Refereed][Not invited]
   

  PURPOSE: Tumor necrosis is one of the indicators of tumor aggressiveness. (18)F-fluoromisonidazole (FMISO) is the most widely used positron emission tomography (PET) tracer to evaluate severe hypoxia in vivo. Because severe hypoxia causes necrosis, we hypothesized that intratumoral necrosis can be detected by FMISO PET in brain tumors regardless of their histopathology. We applied FMISO PET to various types of brain tumors before tumor resection and evaluated the correlation between histopathological necrosis and FMISO uptake. METHODS: This study included 59 brain tumor patients who underwent FMISO PET/computed tomography before any treatments. According to the pathological diagnosis, the brain tumors were divided into three groups: astrocytomas (group 1), neuroepithelial tumors except for astrocytomas (group 2), and others (group 3). Two experienced neuropathologists evaluated the presence of necrosis in consensus. FMISO uptake in the tumor was evaluated visually and semi-quantitatively using the tumor-to-normal cerebellum ratio (TNR). RESULTS: In visual analyses, 26/27 cases in the FMISO-positive group presented with necrosis, whereas 28/32 cases in the FMISO-negative group did not show necrosis. Mean TNRs with and without necrosis were 3.49 ± 0.97 and 1.43 ± 0.42 (p < 0.00001) in group 1, 2.91 ± 0.83 and 1.44 ± 0.20 (p < 0.005) in group 2, and 2.63 ± 1.16 and 1.35 ± 0.23 (p < 0.05) in group 3, respectively. Using a cut-off value of TNR = 1.67, which was calculated by normal reference regions of interest, we could predict necrosis with sensitivity, specificity, and accuracy of 96.7, 93.1, and 94.9 %, respectively. CONCLUSIONS: FMISO uptake within the lesion indicated the presence of histological micro-necrosis. When we used a TNR of 1.67 as the cut-off value, intratumoral micro-necrosis was sufficiently predictable. Because the presence of necrosis implies a poor prognosis, our results suggest that FMISO PET could provide important information for treatment decisions or surgical strategies of any type of brain tumor.
• Imaging Mass Spectrometry Reveals Acyl-Chain- and Region-Specific Sphingolipid Metabolism in the Kidneys of Sphingomyelin Synthase 2-Deficient Mice

  Masayuki Sugimoto, Masato Wakabayashi, Yoichi Shimizu, Takeshi Yoshioka, Kenichi Higashino, Yoshito Numata, Tomohiko Okuda, Songji Zhao, Shota Sakai, Yasuyuki Igarashi, Yuji Kuge

  PLOS ONE 11 (3) e0152191  1932-6203 2016/03 [Refereed][Not invited]
   

  Obesity was reported to cause kidney injury by excessive accumulation of sphingolipids such as sphingomyelin and ceramide. Sphingomyelin synthase 2 (SMS2) is an important enzyme for hepatic sphingolipid homeostasis and its dysfunction is considered to result in fatty liver disease. The expression of SMS2 is also high in the kidneys. However, the contribution of SMS2 on renal sphingolipid metabolism remains unclear. Imaging mass spectrometry is a powerful tool to visualize the distribution and provide quantitative data on lipids in tissue sections. Thus, in this study, we analyzed the effects of SMS2 deficiency on the distribution and concentration of sphingomyelins in the liver and kidneys of mice fed with a normal-diet or a high-fat-diet using imaging mass spectrometry and liquid chromatography/electrospray ionization-tandem mass spectrometry. Our study revealed that high-fat-diet increased C18-C22 sphingomyelins, but decreased C24-sphingomyelins, in the liver and kidneys of wild-type mice. By contrast, SMS2 deficiency decreased C18-C24 sphingomyelins in the liver. Although a similar trend was observed in the whole-kidneys, the effects were minor. Interestingly, imaging mass spectrometry revealed that sphingomyelin localization was specific to each acyl-chain length in the kidneys. Further, SMS2 deficiency mainly decreased C22-sphingomyelin in the renal medulla and C24-sphingomyelins in the renal cortex. Thus, imaging mass spectrometry can provide visual assessment of the contribution of SMS2 on acyl-chain- and region-specific sphingomyelin metabolism in the kidneys.
• Optimization of helical acquisition parameters to preserve uniformity of mouse whole body using multipinhole collimator in single-photon emission computed tomography

  Naoyuki Ukon, Naoki Kubo, Masayori Ishikawa, Songji Zhao, Nagara Tamaki, Yuji Kuge

  Results in Physics 6 659 - 663 2211-3797 2016 [Refereed][Not invited]
   

  Focusing on whole-body uniformity in small-animal single-photon emission computed tomography (SPECT), we examined the optimal helical acquisition parameters using five-pinhole collimators for mouse imaging. SPECT images of an 80-mm-long cylindrical phantom with 99mTc solution were acquired using an Inveon multimodality imaging platform. The bed travels used in this study were 0, 30, 60, 90 and 120 mm, and the numbers of revolutions traversed during the SPECT scan were 1.0, 2.0, 3.0, 4.0, 5.0 and 7.0, respectively. Artifacts that degrade uniformity in reconstructed images were conspicuous when the bed travel was smaller than the object length. Regarding the distal-to-center ratio (DCR) of SPECT values in the object's axial direction, the DCR nearest to the ideal ratio of 1.00 was 1.02 in the optimal uniformity with 4.0 revolutions and a bed travel of 120 mm. Moreover, the helical acquisition using these parameters suppressed the formation of artifacts. We proposed the optimal parameters in whole-body helical SPECT; the bed travel was sufficiently larger than the object length; the 4.0 or more revolutions were required for a pitch of approximately 30 mm/revolution. The optimal acquisition parameters in SPECT to preserve uniformity would contribute to the accurate quantification of whole-body biodistribution. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
• Histological analyses by matrix-assisted laser desorption/ionization-imaging mass spectrometry reveal differential localization of sphingomyelin molecular species regulated by particular ceramide synthase in mouse brains.

  Masayuki Sugimoto, Yoichi Shimizu, Takeshi Yoshioka, Masato Wakabayashi, Yukari Tanaka, Kenichi Higashino, Yoshito Numata, Shota Sakai, Akio Kihara, Yasuyuki Igarashi, Yuji Kuge

  Biochimica et biophysica acta 1851 (12) 1554 - 65 2015/12 [Refereed][Not invited]
   

  Sphingomyelin (SM) is synthesized by SM synthase (SMS) from ceramide (Cer). SM regulates signaling pathways and maintains organ structure. SM comprises a sphingoid base and differing lengths of acyl-chains, but the importance of its various forms and regulatory synthases is not known. It has been reported that Cer synthase (CerS) has restricted substrate specificity, whereas SMS has no specificity for different lengths of acyl-chains. We hypothesized that the distribution of each SM molecular species was regulated by expression of the CerS family. Thus, we compared the distribution of SM species and CerS mRNA expression using molecular imaging. Spatial distribution of each SM molecular species was investigated using ultra-high-resolution imaging mass spectrometry (IMS). IMS revealed that distribution of SM molecular species varied according to the lengths of acyl-chains found in each brain section. Furthermore, a combination study using in situ hybridization and IMS revealed the spatial expression of CerS1 to be associated with the localization of SM (d18:1/18:0) in cell body-rich gray matter, and CerS2 to be associated with SM (d18:1/24:1) in myelin-rich white matter. Our study is the first comparison of spatial distribution between SM molecular species and CerS isoforms, and revealed their distinct association in the brain. These observations were demonstrated by suppression of CerS2 using siRNA in HepG2 cells; that is, siRNA for CerS2 specifically decreased C22 very long-chain fatty acid (VLCFA)- and C24 VLCFA-containing SMs. Thus, histological analyses of SM species by IMS could be a useful approach to consider their molecular function and regulative mechanism.
• The accumulation mechanism of the hypoxia imaging probe "FMISO" by imaging mass spectrometry: possible involvement of low-molecular metabolites

  Yukiko Masaki, Yoichi Shimizu, Takeshi Yoshioka, Yukari Tanaka, Ken-ichi Nishijima, Songji Zhao, Kenichi Higashino, Shingo Sakamoto, Yoshito Numata, Yoshitaka Yamaguchi, Nagara Tamaki, Yuji Kuge

  SCIENTIFIC REPORTS 5 16802  2045-2322 2015/11 [Refereed][Not invited]
   

  F-18-fluoromisonidazole (FMISO) has been widely used as a hypoxia imaging probe for diagnostic positron emission tomography (PET). FMISO is believed to accumulate in hypoxic cells via covalent binding with macromolecules after reduction of its nitro group. However, its detailed accumulation mechanism remains unknown. Therefore, we investigated the chemical forms of FMISO and their distributions in tumours using imaging mass spectrometry (IMS), which visualises spatial distribution of chemical compositions based on molecular masses in tissue sections. Our radiochemical analysis revealed that most of the radioactivity in tumours existed as low-molecular-weight compounds with unknown chemical formulas, unlike observations made with conventional views, suggesting that the radioactivity distribution primarily reflected that of these unknown substances. The IMS analysis indicated that FMISO and its reductive metabolites were nonspecifically distributed in the tumour in patterns not corresponding to the radioactivity distribution. Our IMS search found an unknown low-molecular-weight metabolite whose distribution pattern corresponded to that of both the radioactivity and the hypoxia marker pimonidazole. This metabolite was identified as the glutathione conjugate of amino-FMISO. We showed that the glutathione conjugate of amino-FMISO is involved in FMISO accumulation in hypoxic tumour tissues, in addition to the conventional mechanism of FMISO covalent binding to macromolecules.
• Combined Plasma and Tissue Proteomic Study of Atherogenic Model Mouse: Approach To Elucidate Molecular Determinants in Atherosclerosis Development

  Hiroko Hanzawa, Takeshi Sakamoto, Akihito Kaneko, Naomi Manri, Yan Zhao, Songji Zhao, Nagara Tamaki, Yuji Kuge

  JOURNAL OF PROTEOME RESEARCH 14 (10) 4257 - 4269 1535-3893 2015/10 [Refereed][Not invited]
   

  Atherogenic cardiovascular diseases are the major cause of mortality. Prevention and prediction of incidents is important; however, biomarkers that directly reflect the disease progression remain poorly investigated. To elucidate molecular determinants of atherogenesis, proteomic approaches are advantageous by using model animals for comparing changes occurring systematically (bloodstream) and locally (lesion) in accordance with the disease progression stages. We conducted differential mass spectrometric analysis between apolipoprotein E deficient (apoED) and wild-type (wt) mice using the plasma and arterial tissue of both types of mice obtained at four pathognomonic time points of the disease. A total of 100 proteins in the plasma and 390 in the arterial tissues were continuously detected throughout the four time points; 29 were identified in common. Of those, 13 proteins in the plasma and 36 in the arterial tissues showed significant difference in abundance between the apoED and wt mice at certain time points. Importantly, we found that quantitative variation patterns regarding the pathognomonic time points did not always correspond between the plasma and arterial tissues, resulting in gaining insight into atherosclerotic plaque progression. These characteristic proteins were found to be components of inflammation, thrombus formation, and vascular remodeling, suggesting drastic and integrative alteration in accordance with atherosclerosis development.
• Application of Microreactor to the Preparation of C-11-Labeled Compounds via O-[C-11]Methylation with [C-11]CH3I: Rapid Synthesis of [C-11]Raclopride

  Hidekazu Kawashima, Hiroyuki Kimura, Yuta Nakaya, Kenji Tomatsu, Kenji Arimitsu, Hiroaki Nakanishi, Eiichi Ozeki, Yuji Kuge, Hideo Saji

  CHEMICAL & PHARMACEUTICAL BULLETIN 63 (9) 737 - 740 0009-2363 2015/09 [Refereed][Not invited]
   

  A new radiolabeling method using a microreactor was developed for the rapid synthesis of [C-11]raclopride. A chip bearing a Y-shaped mixing junction with a 200 mu m (width)X20 mu m (depth)x250 mm (length) flow channel was designed, and the efficiency of O-[C-11]methylation was evaluated. Dimethyl sulfoxide solutions containing the O-desmethyl precursor or [C-11]CH3I were introduced into separate injection ports by infusion syringes, and the radiochemical yields were measured under various conditions. The decay-corrected radiochemical yield of microreactor-derived [C-11]raclopride reached 12% in 20s at 25 degrees C, which was observed to increase with increasing temperature. In contrast, batch synthesis at 25 degrees C produced a yield of 5%: this indicates that this device could effectively achieve O-[C-11]methylation in a shorter period of time. The microreactor technique may facilitate simple and efficient routine production of C-11-labeled compounds via O-[C-11]methylation with [C-11]CH3I.
• Relationship between biodistribution of a novel thymidine phosphorylase (TP) imaging probe and TP expression levels in normal mice

  Songji Zhao, Hua Li, Ken-ichi Nishijima, Yan Zhao, Hiromichi Akizawa, Yoichi Shimizu, Kazue Ohkura, Nagara Tamaki, Yuji Kuge

  ANNALS OF NUCLEAR MEDICINE 29 (7) 582 - 587 0914-7187 2015/08 [Refereed][Not invited]
   

  Objective Thymidine phosphorylase (TP) is a key enzyme in the pyrimidine nucleoside salvage pathway and its expression is upregulated in a wide variety of solid tumors. In mice, we previously observed high and specific accumulation levels of our TP imaging probe, radioiodinated 5-iodo-6-[(2-iminoimidazolidinyl)methyl]uracil (IIMU) not only in high-TP-expressing tumors, but also in the liver and small intestine. To clarify the reason for the high accumulation levels of radioiodinated IIMU in the liver and small intestine, we investigated the expression levels of TP in mice in comparison with the biodistribution of radioiodinated IIMU (I-123-IIMU). Methods BALB/cCrSlc mice were injected with I-123-IIMU, and the radioactivity levels [%ID/g (normalized to a mouse of 25 g body weight)] in the tissues of interest were determined 0.5, 1, 3 and 24 h after the injection (n = 5, each time point). To determine the expression levels of TP, BALB/cCrSlc and ddy mice (n = 3/each strain) were euthanized, and the heart, liver, lung, spleen, kidney, stomach, small intestine, large intestine and brain were collected. The mRNA and protein expression levels of TP in these organs were examined by quantitative reverse transcription-polymerase chain reaction and western blot analyses, respectively. Results In BALB/cCrSlc mice administered I-123-IIMU, markedly high radioactivity levels were observed in the liver [1.568 +/- A 0.237 (%ID/g)] and small intestine [0.506 +/- A 0.082 (%ID/g)], whereas those in the other tissues were fairly low [< 0.010 +/- A 0.003 (%ID/g)] 30 min after the injection. The highest expression levels of TP mRNA were also observed in the liver and small intestine among the tissues tested. Immunoblotting showed intense immunoreactive bands of the TP protein for the liver and small intestine, whereas no notable bands were detected for other tissues. Similar expression profiles of TP mRNA and protein were observed in ddy mice. Conclusion We confirmed TP expression in various tissues of mice at the mRNA and protein levels: high TP expression levels were observed in the liver and small intestine. These high TP expression levels are consistent with the high accumulation levels of I-123-IIMU in these tissues. Our results may provide important information about the physiological accumulation of I-123-IIMU, which may be useful for the clinical diagnostic imaging of TP.
• Prognostic value of volume-based measurements on (11)C-methionine PET in glioma patients.

  Kentaro Kobayashi, Kenji Hirata, Shigeru Yamaguchi, Osamu Manabe, Shunsuke Terasaka, Hiroyuki Kobayashi, Tohru Shiga, Naoya Hattori, Shinya Tanaka, Yuji Kuge, Nagara Tamaki

  European journal of nuclear medicine and molecular imaging 42 (7) 1071 - 80 2015/06 [Refereed][Not invited]
   

  PURPOSE: (11)C-methionine (MET) PET is an established diagnostic tool for glioma. Studies have suggested that MET uptake intensity in the tumor is a useful index for predicting patient outcome. Because MET uptake is known to reflect tumor expansion more accurately than MRI, we aimed to elucidate the association between volume-based tumor measurements and patient prognosis. METHODS: The study population comprised 52 patients with newly diagnosed glioma who underwent PET scanning 20 min after injection of 370 MBq MET. The tumor was contoured using a threshold of 1.3 times the activity of the contralateral normal cortex. Metabolic tumor volume (MTV) was defined as the total volume within the boundary. Total lesion methionine uptake (TLMU) was defined as MTV times the mean standardized uptake value (SUVmean) within the boundary. The tumor-to-normal ratio (TNR), calculated as the maximum standardized uptake value (SUVmax) divided by the contralateral reference value, was also recorded. All patients underwent surgery (biopsy or tumor resection) targeting the tissue with high MET uptake. The Kaplan-Meier method was used to estimate the predictive value of each measurement. RESULTS: Grade II tumor was diagnosed in 12 patients (3 diffuse astrocytoma, 2 oligodendroglioma, and 7 oligoastrocytoma), grade III in 18 patients (8 anaplastic astrocytoma, 6 anaplastic oligodendroglioma, and 4 anaplastic oligoastrocytoma), and grade IV in 22 patients (all glioblastoma). TNR, MTV and TLMU were 3.1 ± 1.2, 51.6 ± 49.9 ml and 147.7 ± 153.3 ml, respectively. None of the three measurements was able to categorize the glioma patients in terms of survival when all patients were analyzed. However, when only patients with astrocytic tumor (N = 33) were analyzed (i.e., when those with oligodendroglial components were excluded), MTV and TLMU successfully predicted patient outcome with higher values associated with a poorer prognosis (P < 0.05 and P < 0.01, respectively), while the predictive ability of TNR did not reach statistical significance (P = NS). CONCLUSION: MTV and TLMU may be useful for predicting outcome in patients with astrocytic tumor.
• Oligodendroglial component complicates the prediction of tumour grading with metabolic imaging.

  Osamu Manabe, Naoya Hattori, Shigeru Yamaguchi, Kenji Hirata, Kentaro Kobayashi, Shunsuke Terasaka, Hiroyuki Kobayashi, Hiroaki Motegi, Tohru Shiga, Keiichi Magota, Noriko Oyama-Manabe, Ken-ichi Nishijima, Yuji Kuge, Nagara Tamaki

  European journal of nuclear medicine and molecular imaging 42 (6) 896 - 904 2015/05 [Refereed][Not invited]
   

  PURPOSE: Previous radiological investigations have generally shown the superiority of metabolic imaging in distinguishing high-grade from low-grade glioma, but the presence of an oligodendroglial component may affect the diagnostic accuracy. We investigated the diagnostic accuracy of PET imaging using (11)C-methionine (MET) and (18)F-fluorodeoxyglucose (FDG) in distinguishing high-grade from low-grade glioma, in correlation with the oligodendroglial component. METHODS: The study population comprised adult patients who underwent preoperative PET imaging using both MET and FDG within 1 week and successful excision of the tumour tissue, which confirmed WHO grade II-IV glioma. We examined the tumour metabolic activity in terms of lesion-to-normal uptake ratios (L/N ratio) in both MET PET and FDG PET images. We assessed the correlation between the imaging results and the histological findings to determine the diagnostic accuracy of receiver operating characteristics (ROC) analysis in detecting high-grade tumours. RESULTS: We studied 46 patients with glioma (13 low-grade and 33 high-grade), including 26 with an oligodendroglial components. The L/N ratios of the PET images showed significantly higher metabolic activities in high-grade gliomas than in low-grade gliomas for both MET (4.29 ± 1.22 and 2.36 ± 0.72, respectively; p < 0.0001) and FDG (1.72 ± 0.91 and 0.77 ± 0.26, respectively; p = 0.0007) images, although significant overlaps in L/N ratio were observed between high-grade and low-grade gliomas. Excluding the 26 patents with an oligodendroglial component improved the separation for both MET (4.62 ± 1.14 vs. 2.16 ± 0.63; p < 0.001) and FDG (1.76 ± 0.87 vs. 0.71 ± 0.14; p < 0.05) images. The ROC analyses demonstrated the clinical utility of the metabolic radiotracers in distinguishing high-grade from low-grade gliomas, showing similar AUC values for MET (0.91) and FDG (0.92). Excluding the 26 patents with an oligodendroglial component also further improved the diagnostic accuracy for both MET (AUC 0.98), and FDG (AUC 1.00) images. The metabolic radiotracers were significantly correlated with the MIB-1 labelling index (R = 0.52, p < 0.05 for MET; R = 0.52, p < 0.05, for FDG) only in gliomas without an oligodendroglial component. CONCLUSION: For better characterization of gliomas and for risk assessment, the results of metabolic PET imaging should be revised after obtaining the pathological report, because oligodendroglial differentiation may positively influence the substrate metabolism and thus complicated the preoperative evaluation.
• Differentiation of malignant tumours from granulomas by using dynamic [F-18]-fluoro-L-alpha-methyltyrosine positron emission tomography

  Aiko Yamaguchi, Hirofumi Hanaoka, Yutaka Fujisawa, Songji Zhao, Kazutomo Suzue, Akihiro Morita, Hideyuki Tominaga, Tetsuya Higuchi, Hajime Hisaeda, Yoshito Tsushima, Yuji Kuge, Yasuhiko Iida

  EJNMMI RESEARCH 5 29  2191-219X 2015/04 [Refereed][Not invited]
   

  Background: Previous clinical studies have revealed the potential of [F-18]-fluoro-L-alpha-methyltyrosine (F-18-FAMT) for the differential diagnosis of malignant tumours from sarcoidosis. However, one concern regarding the differential diagnosis with F-18-FAMT is the possibility of false negatives given the small absolute uptake of F-18-FAMT that has been observed in some malignant tumours. The aim of this study was to evaluate a usefulness of dynamic F-18-FAMT positron emission tomography (PET) for differentiating malignant tumours from granulomas. Methods: Rats bearing both granulomas (Mycobacterium bovis bacillus Calmette-Guerin (BCG)-induced) and tumours (C6 glioma cell-induced) underwent dynamic 2-deoxy-2-[F-18]-fluoro-D-glucose (F-18-FDG) PET and F-18-FAMT PET for 120 min on consecutive days. Time-activity curves, static images, mean standardized uptake values (SUVs) and the SUV ratios (SUVRs; calculated by dividing SUV at each time point by that of 2 min after injection) were assessed. Results: In tumours, F-18-FAMT showed a shoulder peak immediately after the initial distribution followed by gradual clearance compared with granulomas. Although the mean SUV in the tumours (1.00 +/- 0.10) was significantly higher than that in the granulomas (0.88 +/- 0.12), a large overlap was observed. In contrast, the SUVR was markedly higher in tumours than in granulomas (50 min/2 min, 0.72 +/- 0.06 and 0.56 +/- 0.05, respectively) with no overlap. The dynamic patterns, SUVR, and mean SUV of F-18-FDG in the granulomas were comparable to those in the tumours. Conclusions: Dynamic F-18-FAMT and SUVR analysis might compensate for the current limitations and help in improving the diagnostic accuracy of F-18-FAMT.
• Radiolabeled BMIPP for Imaging Hepatic Fatty Acid Metabolism: Evaluation of Hepatic Distribution and Metabolism in Mice at Various Metabolic Statuses Induced by Fasting in Comparison with Palmitic Acid

  Kazuaki Yamasaki, Songji Zhao, Mie Nishimura, Yan Zhao, Wenwen Yu, Yoichi Shimizu, Ken-ichi Nishijima, Nagara Tamaki, Hiroshi Takeda, Yuji Kuge

  MOLECULAR IMAGING 14 (0) 1 - 11 1535-3508 2015/04 [Refereed][Not invited]
   

  Abnormalities in hepatic fatty acid metabolism are involved in various diseases. In order to clarify the use of I-123-15-(p-iodophenyl)-3(R,S)-methylpentadecanoic acid ([I-123]BMIPP) for imaging hepatic fatty acid metabolism, we determined the hepatic distribution/metabolism of [I-125]BMIPP in mice at various metabolic statuses induced by fasting, and compared the results with those of [1-C-14]palmitic acid ([1-C-14]PA). Fed or fasted (6, 12, and 24 hour-fasted) mice were intravenously injected with [I-125]BMIPP or [1-C-14]PA. Hepatic radioactivity was measured at 1 to 120 minutes after the injection (n = 5 to 15/time points), and radioactive lipid metabolites were analyzed by thin-layer chromatography (n = 3/time points). The areas under the curves (AUCs) were calculated. In mice given [I-125]BMIPP, the hepatic radioactivity was increased with the fasting time (AUC: 35.1, 45.5, 57.6, and 59.0 [% injected dose (ID)/g/kg].min for fed, 6, 12, and 24 hour-fasted). Similar characteristic changes were observed in mice given [1-C-14]PA (100.6, 101.0, 116.5, and 121.5 [% ID/g/kg].min). Metabolite analysis showed that the triglyceride-fraction was increased by fasting in both groups (5.7, 12.8, 32.0, and 37.9 [% ID/g/kg].min for [I-125] BMIPP groups; 20.6, 39.2, 66.0, and 67.9 [% ID/g/kg].min for [1-C-14]PA groups). Thus, [I-125]BMIPP demonstrated the changes in hepatic fatty acid metabolism induced by fasting, indicating the potential of [I-123]BMIPP for imaging hepatic fatty acid metabolism.
• Regulatory Effect of Interleukin-4 in the Innate Inflammatory Response to Rhodococcus aurantiacus Infection in Mice

  Yimin, Masashi Kohanawa, Songji Zhao, Minqi Li, Yuji Kuge, Nagara Tamaki, Masahiko Watanabe

  JOURNAL OF INTERFERON AND CYTOKINE RESEARCH 35 (3) 222 - 231 1079-9907 2015/03 [Refereed][Not invited]
   

  Interleukin (IL)-4 promotes the regression of granulomas during the late phase of Rhodococcus aurantiacus infection. In this study, the contribution of IL-4 to the initial response against this bacterium was investigated using IL-4-deficient mice. Compared with wild-type (WT) mice, IL-4-deficient mice displayed remarkably lower tumor necrosis factor (TNF)-alpha and IL-6 secretion in the liver, spleen, and blood at the initial phase of infection, along with improved survival. IL-4-deficient mice also showed diminished IL-10 secretion in the spleen and blood; however, hepatic IL-10 levels were similar to those observed in WT animals, and were concomitant with augmented interferon (IFN)-gamma production and decreased bacterial burden in the liver at the early infection phase. Histological examination revealed reduced hepatic granuloma formation in infected IL-4-deficient mice. On challenge with heat-killed R. aurantiacus, IL-4-deficient mouse macrophages showed reduced expression of TNF-alpha, IL-6, and IL-10 at both the gene and protein levels compared with WT mouse cells. These findings indicate that during the initiation of R. aurantiacus-induced inflammation, IL-4 deficiency attenuates cytokine responses in macrophages, which contributes to amelioration in mouse survival and reduction of granulomatous inflammation, and augments a hepatic IFN-gamma response which transiently accelerates bacterial elimination.
• Irbesartan attenuates atherosclerosis in Watanabe Heritable Hyperlipidemic rabbits: Noninvasive imaging of inflammation by 18F-FDG PET

  Zhao Y, Fukao K, Zhao S, Watanabe A, Hamada T, Yamasaki K, Shimizu Y, Kubo N, Ukon N, Nakano T, Tamaki N, Kuge Y

  Mol Imaging 14 (0) 1 - 8 2015 [Refereed][Not invited]
  
• Prone-position acquisition of myocardial (123)I-metaiodobenzylguanidine (MIBG) SPECT reveals regional uptake similar to that found using (11)C-hydroxyephedrine PET/CT.

  Keiichiro Yoshinaga, Yuuki Tomiyama, Osamu Manabe, Katsuhiko Kasai, Chietsugu Katoh, Kenichi Magota, Eriko Suzuki, Ken-Ichi Nishijima, Yuji Kuge, Yoichi M Ito, Nagara Tamaki

  Annals of nuclear medicine 28 (8) 761 - 9 2014/10 [Refereed][Not invited]
   

  OBJECTIVES: (123)I-metaiodobenzylguanidine (MIBG) has been used to estimate cardiac sympathetic nervous innervation. Heterogeneous MIBG distribution is mainly associated with high physiological MIBG uptakes in the liver. We postulate that prone position acquisition might be especially effective for MIBG, providing for separation from high liver uptake similar to that provided by perfusion single-photon emission computed tomography (SPECT). We investigated whether prone-position acquisition improved MIBG image quality by comparing our results to those acquired using supine MIBG and high-quality (11)C-hydroxyephedrine (HED) positron emission tomography/computed tomography PET/CT. METHODS: Ten male volunteers (body mass index (BMI) 22.7 ± 3.4) underwent prone and supine MIBG and HED PET. Relative regional tracer uptake was estimated in early MIBG and HED. Acquired images were divided into 17 segments and were grouped into 4 regions: anterior, inferior, septum, and lateral. For each patient, the inferior/anterior ratio was calculated. RESULTS: The quality of images acquired using prone MIBG was better than that using supine MIBG (p < 0.05). Inferior and septum relative MIBG uptake was reduced in comparison with anterior or lateral MIBG uptake in the supine position (inferior vs. anterior: 69.0 ± 5.6 vs. 82.3 ± 4.6 %, p < 0.01; septum vs. lateral: 66.2 ± 5.1 vs. 81.9 ± 5.4 %, p < 0.01). Prone MIBG showed a significantly higher inferior/anterior uptake ratio in comparison with supine MIBG (n = 24, seg: 92.2 ± 7.2 vs. 83.6 ± 5.7 %, p < 0.05). However, intergroup differences in uptake ratio were demonstrated among prone and supine MIBG and HED. HED PET/CT still showed a higher uptake ratio in comparison with prone MIBG SPECT (103.9 ± 8.0 vs. 92.2 ± 7.2 %, p < 0.05). CONCLUSION: Even in normal male subjects, standard supine MIBG imaging showed reduced inferior and septum uptake. Uptake with prone MIBG imaging showed a significant improvement over that with supine imaging and was closer to uptake for HED PET/CT. This improvement may be the result of preventing intense uptake by the liver. Prone data acquisition may be a viable alternative in evaluating regional abnormalities using MIBG SPECT in men.
• A Simple and Rapid Method for Standard Preparation of Gas Phase Extract of Cigarette Smoke

  Tsunehito Higashi, Yosuke Mai, Yoichi Noya, Takahiro Horinouchi, Koji Terada, Akimasa Hoshi, Prabha Nepal, Takuya Harada, Mika Horiguchi, Chizuru Hatate, Yuji Kuge, Soichi Miwa

  PLOS ONE 9 (9) e107856  1932-6203 2014/09 [Refereed][Not invited]
   

  Cigarette smoke consists of tar and gas phase: the latter is toxicologically important because it can pass through lung alveolar epithelium to enter the circulation. Here we attempt to establish a standard method for preparation of gas phase extract of cigarette smoke (CSE). CSE was prepared by continuously sucking cigarette smoke through a Cambridge filter to remove tar, followed by bubbling it into phosphate-buffered saline (PBS). An increase in dry weight of the filter was defined as tar weight. Characteristically, concentrations of CSEs were represented as virtual tar concentrations, assuming that tar on the filter was dissolved in PBS. CSEs prepared from smaller numbers of cigarettes (original tar concentrations <= 15 mg/ml) showed similar concentration-response curves for cytotoxicity versus virtual tar concentrations, but with CSEs from larger numbers (tar >= 20 mg/ml), the curves were shifted rightward. Accordingly, the cytotoxic activity was detected in PBS of the second reservoir downstream of the first one with larger numbers of cigarettes. CSEs prepared from various cigarette brands showed comparable concentration-response curves for cytotoxicity. Two types of CSEs prepared by continuous and puff smoking protocols were similar regarding concentration-response curves for cytotoxicity, pharmacology of their cytotoxicity, and concentrations of cytotoxic compounds. These data show that concentrations of CSEs expressed by virtual tar concentrations can be a reference value to normalize their cytotoxicity, irrespective of numbers of combusted cigarettes, cigarette brands and smoking protocols, if original tar concentrations are <= 15 mg/ml.
• Dual tracer evaluation of dynamic changes in intratumoral hypoxic and proliferative states after radiotherapy of human head and neck cancer xenografts using radiolabeled FMISO and FLT

  Chowdhury Nusrat Fatema, Songji Zhao, Yan Zhao, Wenwen Yu, Ken-ichi Nishijima, Koichi Yasuda, Yoshimasa Kitagawa, Nagara Tamaki, Yuji Kuge

  BMC CANCER 14 (1) 692  1471-2407 2014/09 [Refereed][Not invited]
   

  Background: Radiotherapy is an important treatment strategy for head and neck cancers. Tumor hypoxia and repopulation adversely affect the radiotherapy outcome. Accordingly, fractionated radiotherapy with dose escalation or altered fractionation schedule is used to prevent hypoxia and repopulation. F-18-fluoromisonidazole (FMISO) and F-18-fluorothymidine (FLT) are noninvasive markers for assessing tumor hypoxia and proliferation, respectively. Thus, we evaluated the dynamic changes in intratumoral hypoxic and proliferative states following radiotherapy using the dual tracers of F-18-FMISO and H-3-FLT, and further verified the results by immunohistochemical staining of pimonidazole (a hypoxia marker) and Ki-67 (a proliferation marker) in human head and neck cancer xenografts (FaDu). Methods: FaDu xenografts were established in nude mice and assigned to the non-radiation-treated control and two radiation-treated groups (10- and 20-Gy). Tumor volume was measured daily. Mice were sacrificed 6, 24, and 48 hrs and 7 days after radiotherapy. F-18-FMISO, and H-3-FLT and pimonidazole were injected intravenously 4 and 2 hrs before sacrifice, respectively. Intratumoral F-18-FMISO and H-3-FLT levels were assessed by autoradiography. Pimonidazole and Ki-67 immunohistochemistries were performed. Results: In radiation-treated mice, tumor growth was significantly suppressed compared with the control group, but the tumor volume in these mice gradually increased with time. Visual inspection showed that intratumoral F-18-FMISO and H-3-FLT distribution patterns were markedly different. Intratumoral F-18-FMISO level did not show significant changes after radiotherapy among the non-radiation-treated control and radiation-treated groups, whereas H-3-FLT level markedly decreased to 59 and 45% of the non-radiation-treated control at 6 hrs (p < 0.0001) and then gradually increased with time in the 10- and 20-Gy-radiation-treated groups. The pimonidazole-positive hypoxic areas were visually similar in both the non-radiation-treated control and radiation-treated groups. No significant differences were observed in the percentage of pimonidazole-positive cells and Ki-67 index. Conclusion: Intratumoral F-18-FMISO level did not change until 7 days, whereas H-3-FLT level markedly decreased at 6 hrs and then gradually increased with time after a single dose of radiotherapy. The concomitant monitoring of dynamic changes in tumor hypoxia and proliferation may provide important information for a better understanding of tumor biology after radiotherapy and for radiotherapy planning, including dose escalation and altered fractionation schedules.
• Evaluation of delineation of image details in semiconductor PET utilizing the normalized mutual information technique

  Naoki Kubo, Kenji Hirata, Kazuki Matsuzaki, Yuichi Morimoto, Wataru Takeuchi, Naoya Hattori, Tohru Shiga, Yuji Kuge, Nagara Tamaki

  NUCLEAR MEDICINE COMMUNICATIONS 35 (6) 677 - 682 0143-3636 2014/06 [Refereed][Not invited]
   

  Objective PET using semiconductor detectors provides high-quality images of the human brain because of its high spatial resolution. To quantitatively evaluate the delineation of image details in clinical PET images, we used normalized mutual information (NMI) to quantify the similarity with images obtained through MRI. NMI is used to evaluate image quality by determining similarity with a reference image. The aim of this study was to evaluate quantitatively the delineation of image details provided by semiconductor PET. Materials and methods To quantitatively evaluate anatomical delineation in clinical PET images, MRI scans of patients were used as T1-weighted images. [F-18]-fluorodeoxyglucose (F-18-FDG) PET brain images were obtained from six patients using (a) a Hitachi semiconductor PET scanner and (b) a ECAT HR+ scintillator PET scanner. The NMI calculated from the semiconductor PET and MRI was denoted by NMIsemic, whereas the NMI calculated from conventional scintillator PET and MRI was denoted by NMIconve. The higher the value of NMI, the greater the similarity to MRI. Results NMIsemic ranged from 1.22 to 1.29, whereas NMIconve ranged from 1.13 to 1.18 (P < 0.05). Furthermore, all the NMI values of the semiconductor PET were higher than those of the conventional scintillator PET. Conclusion Utilizing NMI, we quantitatively evaluated the delineation of image details in clinical PET images. The results reveal that semiconductor PET has superior anatomical delineation and physical performance compared with conventional scintillator PET. This improved delineation of image details makes semiconductor PET promising for clinical applications.
• Electrocardiographically gated ¹¹C-hydroxyephedrine PET for the simultaneous assessment of cardiac sympathetic and contractile functions.

  Keiichi Magota, Naoya Hattori, Osamu Manabe, Masanao Naya, Noriko Oyama-Manabe, Tohru Shiga, Yuji Kuge, Shiro Yamada, Mamoru Sakakibara, Keiichiro Yoshinaga, Nagara Tamaki

  Annals of nuclear medicine 28 (3) 187 - 95 2014/04 [Refereed][Not invited]
   

  OBJECTIVE: Application of the electrocardiographically (ECG) gated positron emission tomography (PET) technique with (11)C-hydroxyephedrine (HED) would allow the simultaneous assessment of cardiac sympathetic and contractile functions. However, there are uncertainties regarding the diagnostic accuracy of left ventricular (LV) volume measurements using ECG-gated HED-PET. The purpose of this study was to clarify the minimal requirement of count statistics to measure LV volumes with ECG-gated HED-PET and to investigate the reliability of the measurements. METHODS: Five healthy volunteers and 11 patients with heart failure underwent a 40-min list-mode PET scan after an injection of HED (197 ± 35 MBq). The list-mode data were histogrammed into multiple sets of acquisition periods at 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, 12.0 Mcount/bin and reconstructed into corresponding gated images using an iterative algorithm. The LV end-diastolic volume (LVEDV), the LV end-systolic volume (LVESV), and the LV ejection fraction (LVEF) were calculated in each acquisition period. These values were compared with those obtained by cardiac magnetic resonance imaging (MRI). Possible effects of HED retention on the accuracy of the volume measurements were investigated. RESULTS: Collecting less than 4.0 Mcount/bin resulted in noisy cardiac images. The lower counts resulted in underestimation in the volume measurements. Reasonably accurate volume measurements required equal to or greater than 6.0 Mcount/bin. This corresponded to 7.0 ± 1.9 min (range, 4.0-10.3 min) for the acquisition period. Volumetric results using the 6.0 Mcount/bin data highly correlated with cardiac MRI (LVEDV: r = 0.85, p < 0.0001; LVESV: r = 0.89, p < 0.0001; LVEF: r = 0.77, p < 0.01). The HED retention did not affect the volumetric results compared to the MRI volumetry. CONCLUSIONS: The volumetric accuracy with ECG-gated HED-PET was affected by the count statistics rather than the HED retention. LV volume measurements were feasible with 10-min acquisition period for most of the patients. This technique allows the simultaneous assessment of cardiac sympathetic and contractile functions without the need for an additional injection or scanning time, thus reducing overall costs for diagnostic imaging.
• Suppressive Effects of Irbesartan on Inflammation and Apoptosis in Atherosclerotic Plaques of apoE(-/-) Mice: Molecular Imaging with C-14-FDG and Tc-99m-Annexin A5

  Yan Zhao, Ayahisa Watanabe, Songji Zhao, Tatsuo Kobayashi, Keita Fukao, Yoshikazu Tanaka, Toru Nakano, Tetsuya Yoshida, Hiroshi Takemoto, Nagara Tamaki, Yuji Kuge

  PLOS ONE 9 (2) e89338  1932-6203 2014/02 [Refereed][Not invited]
   

  Objectives: To investigate the effects of irbesartan on inflammation and apoptosis in atherosclerotic plaques by histochemical examination and molecular imaging using C-14-FDG and Tc-99m-annexin A5. Background: Irbesartan has a peroxisome proliferator-activated receptor gamma (PPAR gamma) activation property in addition to its ability to block the AT1 receptor. Accordingly, irbesartan may exert further anti-inflammatory and anti-apoptotic effects in atherosclerotic plaques. However, such effects of irbesartan have not been fully investigated. Molecular imaging using F-18-FDG and Tc-99m-annexin A5 is useful for evaluating inflammation and apoptosis in atherosclerotic plaques. Methods: Female apoE(-/-) mice were treated with irbesartan-mixed (50 mg/kg/day) or irbesartan-free (control) diet for 12 weeks (n = 11/group). One week after the treatment, the mice were co-injected with C-14-FDG and Tc-99m-annexin A5, and cryostat sections of the aortic root were prepared. Histochemical examination with Movat's pentachrome (plaque size), Oil Red O (lipid deposition), Mac-2 (macrophage infiltration), and TUNEL (apoptosis) stainings were performed. Dual-tracer autoradiography was carried out to evaluate the levels of C-14-FDG and Tc-99m-annexin A5 in plaques (% IDxkg). In vitro experiments were performed to investigate the mechanism underlying the effects. Results: Histological examination indicated that irbesartan treatment significantly reduced plaque size (to 56.4% +/- 11.1% of control), intra-plaque lipid deposition (53.6%+/- 20.2%) and macrophage infiltration (61.9% +/- 20.8%) levels, and the number of apoptotic cells (14.5%+/- 16.6%). C-14-FDG (43.0% +/- 18.6%) and Tc-99m-annexin A5 levels (45.9% +/- 16.8%) were also significantly reduced by irbesartan treatment. Irbesartan significantly suppressed MCP-1 mRNA expression in TNF-alpha stimulated THP-1 monocytes (64.8% +/- 8.4% of un-treated cells). PPAR gamma activation was observed in cells treated with irbesartan (134% +/- 36% at 3 mu M to 3329% +/- 218% at 81 mu M) by a PPAR gamma reporter assay system. Conclusions: Remissions of inflammation and apoptosis as potential therapeutic effects of irbesartan on atherosclerosis were observed. The usefulness of molecular imaging using F-18-FDG and Tc-99m-annexin A5 for evaluating the therapeutic effects of irbesartan on atherosclerosis was also suggested.
• Design, synthesis and biological evaluation of negatively charged In-111-DTPA-octreotide derivatives

  Nobuhiro Oshima, Hiromichi Akizawa, Songji Zhao, Yan Zhao, Ken-ichi Nishijima, Yoji Kitamura, Yasushi Arano, Yuji Kuge, Kazue Ohkura

  BIOORGANIC & MEDICINAL CHEMISTRY 22 (4) 1377 - 1382 0968-0896 2014/02 [Refereed][Not invited]
   

  Our previous studies indicated that In-111-diethylenetriaminepentaacetic acid (In-111-DTPA)-octreotide derivatives with an additional negative charge by replacing N-terminal D-phenylalanine (D-Phe) with an acidic amino acid such as L-aspartic acid (Asp) or its derivative exhibited low renal radioactivity levels when compared with In-111-DTPA-D-Phe(1)-octreotide. On the basis of the findings, we designed, synthesized and evaluated two Asp-modified In-111-DTPA-conjugated octreotide derivatives, In-111-DTPA-Asp(1)-octreotide and In-111-DTPA-Asp(0)-D-Phe(1)-octreotide. While In-111-DTPA-Asp1-octreotide showed negligible AR42J cell uptake, In-111-DTPA-Asp(0)-D-Phe(1)-octreotide exhibited AR42J cell uptake similar to that of In-111-DTPA-D-Phe(1)-octreotide. When administered to AR42J tumor-bearing mice, In-111-DTPA-Asp(0)-D-Phe(1)-octreotide exhibited renal radioactivity levels significantly lower than did In-111-DTPA-D-Phe(1)-octreotide at 1 and 3 h post-injection. No significant differences were observed in tumor accumulation between In-111-DTPA-Asp(0)-D-Phe(1)-octreotide and In-111-DTPA-D-Phe(1)-octreotide after 1 and 3 h injection. The findings in this study suggested that an interposition of an Asp at an appropriate position in In-111-DTPA-D-Phe(1)-octreotide would constitute a useful strategy to develop In-111-DTPA-D-Phe(1)-octreotide derivatives of low renal radioactivity levels while preserving tumor accumulation. (C) 2014 Elsevier Ltd. All rights reserved.
• Advantage of FMISO-PET over FDG-PET for predicting histological response to preoperative chemotherapy in patients with oral squamous cell carcinoma

  Jun Sato, Yoshimasa Kitagawa, Yutaka Yamazaki, Hironobu Hata, Takuya Asaka, Masaaki Miyakoshi, Shozo Okamoto, Tohru Shiga, Masanobu Shindoh, Yuji Kuge, Nagara Tamaki

  European Journal of Nuclear Medicine and Molecular Imaging 41 (11) 2031 - 2041 1619-7089 2014 [Refereed][Not invited]
   

  Methods: This study enrolled 22 patients with OSCC undergoing preoperative chemotherapy. The T-stages were T2 in 6 patients, T3 in 3, and T4a in 13, and the N-stages were N0 in 14 patients, N1 in 3, and N2 in 5. Each patient was evaluated by both FMISO-PET and FDG-PET before surgery, and the maximum standardized uptake value (SUV< inf> max< /inf> ) of FDG- and FMISO-PET and tumor-muscle ratio (TMR) of FMISO-PET were measured. The threshold for the hypoxic volume based on TMR was set at 1.25. The histological response to preoperative chemotherapy was evaluated using operative materials. Results: FMISO-PET and FDG-PET detected uptake by primary OSCCs in 15 (68 %) and 21 (95 %) patients, respectively, and median SUV< inf> max< /inf> s of FMISO- and FDG-PET in the primary site were 2.0 (range, 1.3–3.5) and 16.0 (range, 1.0–32.2), respectively. The median of FMISO TMR was 1.5 (range, 0.99–2.96). There were five cases whose FMISO TMR was less than 1.25. Histological evaluation showed good response to preoperative chemotherapy in 7 patients (32 %) and poor response in 15 (68 %). Good response was significantly more prevalent in patients with negative than positive FMISO uptake (P < 0.001) and without the hypoxic area evaluated by FMISO-PET TMR (P = 0.04), whereas FDG uptake was not significantly correlated with response to chemotherapy response. Multivariate logistic regression analysis showed that FMISO uptake was an independent significant predictor of response to preoperative chemotherapy (P = 0.03, odds ratio = 0.06, 95 % confidence interval = 0.004–0.759). Conclusions: An advantage of FMISO-PET over FDG-PET for predicting histological response to preoperative chemotherapy in patients with OSCC was observed. Purpose: Hypoxia, a prognostic factor in many types of cancer, can be detected by < sup> 18< /sup> F-fluoromisonidazole (FMISO) positron emission tomography (PET). It is unclear whether hypoxia reflects the response to chemotherapy in patients with oral squamous cell carcinoma (OSCC). The correlations of FMISO-PET and FDG-PET with histological response to preoperative chemotherapy were therefore assessed in patients with OSCC.
• Increased Metabolite Levels of Glycolysis and Pentose Phosphate Pathway in Rabbit Atherosclerotic Arteries and Hypoxic Macrophage

  Atsushi Yamashita, Yan Zhao, Yunosuke Matsuura, Kazuaki Yamasaki, Sayaka Moriguchi-Goto, Chihiro Sugita, Takashi Iwakiri, Nozomi Okuyama, Chihiro Koshimoto, Keiichi Kawai, Nagara Tamaki, Songji Zhao, Yuji Kuge, Yujiro Asada

  PLOS ONE 9 (1) e86426  1932-6203 2014/01 [Refereed][Not invited]
   

  Aims: Inflammation and possibly hypoxia largely affect glucose utilization in atherosclerotic arteries, which could alter many metabolic systems. However, metabolic changes in atherosclerotic plaques remain unknown. The present study aims to identify changes in metabolic systems relative to glucose uptake and hypoxia in rabbit atherosclerotic arteries and cultured macrophages. Methods: Macrophage-rich or smooth muscle cell (SMC)-rich neointima was created by balloon injury in the iliac-femoral arteries of rabbits fed with a 0.5% cholesterol diet or a conventional diet. THP-1 macrophages stimulated with lipopolysaccharides (LPS) and interferon-c (INF gamma) were cultured under normoxic and hypoxic conditions. We evaluated comprehensive arterial and macrophage metabolism by performing metabolomic analyses using capillary electrophoresis-time of flight mass spectrometry. We evaluated glucose uptake and its relationship to vascular hypoxia using F-18-fluorodeoxyglucose (F-18-FDG) and pimonidazole, a marker of hypoxia. Results: The levels of many metabolites increased in the iliac-femoral arteries with macrophage-rich neointima, compared with those that were not injured and those with SMC-rich neointima (glycolysis, 4 of 9; pentose phosphate pathway, 4 of 6; tricarboxylic acid cycle, 4 of 6; nucleotides, 10 of 20). The uptake of F-18-FDG in arterial walls measured by autoradiography positively correlated with macrophage-and pimonidazole-immunopositive areas (r = 0.76, and r = 0.59 respectively; n = 69 for both; p<0.0001). Pimonidazole immunoreactivity was closely localized with the nuclear translocation of hypoxia inducible factor-1 alpha and hexokinase II expression in macrophage-rich neointima. The levels of glycolytic (8 of 8) and pentose phosphate pathway (4 of 6) metabolites increased in LPS and INF gamma stimulated macrophages under hypoxic but not normoxic condition. Plasminogen activator inhibitor-1 protein levels in the supernatant were closely associated with metabolic pathways in the macrophages. Conclusion: Infiltrative macrophages in atherosclerotic arteries might affect metabolic systems, and hypoxia but not classical activation might augment glycolytic and pentose phosphate pathways in macrophages.
• Identification of stable cytotoxic factors in the gas phase extract of cigarette smoke and pharmacological characterization of their cytotoxicity

  Yoichi Noya, Koh-ichi Seki, Hiroshi Asano, Yosuke Mai, Takahiro Horinouchi, Tsunehito Higashi, Koji Terada, Chizuru Hatate, Akimasa Hoshi, Prabha Nepal, Mika Horiguchi, Yuji Kuge, Soichi Miwa

  Toxicology 314 (1) 1 - 10 1879-3185 2013/12/06 [Refereed][Not invited]
   

  Smoking is a major risk factor for atherosclerotic vascular diseases, but the mechanism for its genesis is unknown. We have recently shown that the gas phase of cigarette smoke (nicotine- and tar-free cigarette smoke extract CSE) likely to reach the systemic circulation contains stable substances which cause cytotoxicity like plasma membrane damage and cell death in cultured cells, and also that the plasma membrane damage is caused through sequential activation of protein kinase C (PKC) and NADPH oxidase (NOX) and the resulting generation of reactive oxygen species (PKC/NOX-dependent mechanism), whereas cell death is caused through PKC/NOX-dependent and -independent mechanisms. To identify these stable substances, the CSE was prepared by passing the main-stream smoke of 10 cigarettes through a Cambridge glass fiber filter, trapping of the smoke in a vessel cooled at -80°C, and subsequent dissolution in 10ml of water. The CSE was fractionated into nine fractions using reversed-phase HPLC, and each fraction was screened for cytotoxicity in cultured cells, using propidium iodide uptake assay for cell membrane damage and MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] reduction assay for cell viability. The cytotoxicity was positive in two of the nine fractions (Fr2 and Fr5). After extraction of the active fractions into dichloromethane, GC/MS analysis identified 2-cyclopenten-1-one (CPO) in Fr5 but none in Fr2. After derivatization of the active fractions with O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride, GC/MS analysis identified acrolein, acetone and propionaldehyde in Fr2, and methyl vinyl ketone (MVK) in Fr5. After 4-h incubation, authentic acrolein and MVK induced concentration-dependent cytotoxicity with EC50 values of 75.9±8.2 and 47.0±8.0μM (mean±SEM n=3), respectively, whereas acetone, propionaldehyde and CPO were without effect. However, after 24-h incubation, CPO induced concentration-dependent cytotoxicity with an EC50 value of 264.0±16.9μM (n=3). The concentrations of acrolein, MVK and CPO in the CSE were 3368±334, 2429±123 and 392.9±31.8μM (n=4), respectively, which were higher than the cytotoxic concentrations. The cytotoxicity of acrolein and MVK consisted of plasma membrane damage and decreased cell viability: the plasma membrane damage was totally prevented by treatment with an inhibitor of PKC or NOX, whereas the decreased cell viability was only partially prevented by these inhibitors. The cytotoxicity of CPO consisted only of decreased cell viability, which was totally resistant to these inhibitors. These results show that acrolein and MVK are responsible for the acute cytotoxicity of the CSE through PKC/NOX-dependent and -independent mechanisms, whereas CPO is responsible for the delayed cytotoxicity of the CSE through a PKC/NOX-independent mechanism. © 2013 Elsevier Ireland Ltd.
• Assessment of early changes in H-3-fluorothymidine uptake after treatment with gefitinib in human tumor xenograft in comparison with Ki-67 and phospho-EGFR expression

  Songji Zhao, Yuji Kuge, Yan Zhao, Satoshi Takeuchi, Kenji Hirata, Toshiki Takei, Tohru Shiga, Hirotoshi Dosaka-Akita, Nagara Tamaki

  BMC CANCER 13 (1) 525  1471-2407 2013/11 [Refereed][Not invited]
   

  Background: The purpose of this study was to evaluate whether early changes in 3'-deoxy-3'-H-3-fluorothymidine (H-3-FLT) uptake can reflect the antiproliferative effect of gefitinib in a human tumor xenograft, in comparison with the histopathological markers, Ki-67 and phosphorylated EGFR (phospho-EGFR). Methods: An EGFR-dependent human tumor xenograft model (A431) was established in female BALB/c athymic mice, which were divided into three groups: one control group and two treatment groups. Mice in the treatment groups were orally administered a partial regression dose (100 mg/kg/day) or the maximum tolerated dose of gefitinib (200 mg/kg/day), once daily for 2 days. Mice in the control group were administered the vehicle (0.1% Tween 80). Tumor size was measured before and 3 days after the start of treatment. Biodistribution of H-3-FLT and F-18-FDG (%ID/g/kg) was examined 3 days after the start of the treatment. Tumor cell proliferative activity with Ki-67 was determined. Immunohistochemical staining of EGFR and measurement of phospho-EGFR were also performed. Results: High expression levels of EGFR and Ki-67 were observed in the A431 tumor. After the treatment with 100 and 200 mg/kg gefitinib, the uptake levels of H-3-FLT in the tumor were significantly reduced to 67% and 61% of the control value, respectively (0.39 +/- 0.09, 0.36 +/- 0.06, 0.59 +/- 0.11% ID/g/kg for 100 mg/kg, 200 mg/kg, and control groups, respectively; p < 0.01 vs. control), but those of F-18-FDG were not. After the treatment with 100 and 200 mg/kg gefitinib, the expression levels of Ki-67 in the tumor were markedly decreased (4.6 +/- 2.4%, 6.2 +/- 1.8%,and 10.4 +/- 5.7% for 100 mg/kg, 200 mg/kg, and control groups, respectively, p < 0.01 vs. control). The expression levels of the phospho-EGFR protein also significantly decreased (29% and 21% of the control value for 100, and 200 mg/kg, respectively p < 0.01 vs. control). There was no statistically significant difference in tumor size between pre- and post-treatments in each group. Conclusion: In our animal model, H-3-FLT uptake levels significantly decreased after the treatment with two different doses of gefitinib before a significant change in tumor size was observed. These results were confirmed by the immunohistochemical staining of Ki-67 and phospho-EGFR protein immunoassay. Thus, it was indicated that early changes in H-3-FLT uptake may reflect the antiproliferative effect of gefitinib in a mouse model of a human epidermoid cancer.
• I-123-Iomazenil Single Photon Emission Computed Tomography Visualizes Recovery of Neuronal Integrity by Bone Marrow Stromal Cell Therapy in Rat Infarct Brain

  Hisayasu Saito, Keiichi Magota, Songji Zhao, Naoki Kubo, Yuji Kuge, Hideo Shichinohe, Kiyohiro Houkin, Nagara Tamaki, Satoshi Kuroda

  STROKE 44 (10) 2869 - 2874 0039-2499 2013/10 [Refereed][Not invited]
   

  Background and Purpose This study was aimed to assess whether I-123-iomazenil (IMZ) single photon emission computed tomography can serially monitor the effects of bone marrow stromal cell (BMSC) transplantation on neuronal integrity in infarct brain of rats. Methods The BMSCs were harvested from green fluorescent protein-transgenic rats and were cultured. The rats were subjected to permanent middle cerebral artery occlusion. Their motor function was serially quantified throughout the experiments. The BMSCs or vehicle was stereotactically transplanted into the ipsilateral striatum at 7 days after the insult. Using small-animal single photon emission computed tomography/computed tomography apparatus, the I-123-IMZ uptake was serially measured at 6 and 35 days after the insult. Finally, fluorescence immunohistochemistry was performed to evaluate the distribution of engrafted cells and their phenotypes. Results The distribution of I-123-IMZ was markedly decreased in the ipsilateral neocortex at 6 days postischemia. The vehicle-transplanted animals did not show a significant change at 35 days postischemia. However, BMSC transplantation significantly improved the distribution of I-123-IMZ in the peri-infarct neocortex as well as motor function. The engrafted BMSCs were densely distributed around cerebral infarct, and some of them expressed neuronal nuclear antigen and -aminobutyric acid type-A receptor. Conclusions The present findings strongly suggest that the BMSCs may enhance functional recovery by improving the neuronal integrity in the peri-infarct area, when directly transplanted into the infarct brain at clinically relevant timing. I-123-IMZ single photon emission computed tomography may be a promising modality to scientifically prove the beneficial effects of BMSC transplantation on the host brain in clinical situation.
• Contribution of Toll-Like Receptor 2 to the Innate Response against Staphylococcus aureus Infection in Mice

  Yimin, Masashi Kohanawa, Songji Zhao, Michitaka Ozaki, Sanae Haga, Guangxian Nan, Yuji Kuge, Nagara Tamaki

  PLoS ONE 8 (9) e74287  1932-6203 2013/09/13 [Refereed][Not invited]
   

  Staphylococcus aureus is a common pathogen that causes a wide range of infectious diseases. The function of TLRs, specifically TLR2, during S. aureus infection is still debated. In this study, we investigated the extent to which TLR2 contributes to the host innate response against the bacterial infection using TLR2-deficient mice. Intravenous inoculation with S. aureus resulted in all TLR2-deficient mice dying within 4 d, along with a high bacterial burden in the livers. However, histological examination showed the same degree of macrophage and neutrophil accumulation in the livers of infected TLR2-deficient mice as that in infected wild-type (WT) mice. TLR2-deficient mouse macrophages also showed normal phagocytic activity, although they failed to express CD36 that appeared on the surface of WT mouse cells upon challenge with heat-killed S. aureus. These data indicate that TLR2, as well as CD36, does not directly affect S. aureus clearance and that CD36 expression on macrophages depends on the presence of TLR2. In vivo infection with S. aureus caused significantly elevated production of TNF-α and IL-6 in the livers and blood of TLR2-deficient mice compared with those in WT mice, while the hepatic and serum levels of IL-10 decreased in these mice. In contrast, lower expression of IL-6 and IL-10, but not of TNF-α, at both the gene and protein levels was found in TLR2-deficient mouse macrophages compared to that in WT mouse cells, in response to challenge with heat-killed S. aureus. These findings suggest that the S. aureus-induced pro-inflammatory cytokine response is not dependent on macrophages and that TLR2 deficiency results in decreased IL-10 release by macrophages, which contributes to dysregulated cytokine balance, impaired bacterial clearance, and mouse death. Therefore, TLR2 possesses a protective function during S. aureus infection by regulating pro- and anti-inflammatory cytokine responses. © 2013 Yimin et al.
• Increased intratumoral fluorothymidine uptake levels following multikinase inhibitor sorafenib treatment in a human renal cell carcinoma xenograft model

  Masahiro Murakami, Songji Zhao, Yan Zhao, Wenwen Yu, Chowdhury Nusrat Fatema, Ken-Ichi Nishijima, Masahiro Yamasaki, Mitsuyoshi Takiguchi, Nagara Tamaki, Yuji Kuge

  Oncology Letters 6 (3) 667 - 672 1792-1074 2013/09 [Refereed][Not invited]
   

  An early identification of the tumor response to sorafenib treatment is indispensable for selecting optimal personalized treatment strategies. However, at present, no reliable predictors are clinically available. 18F-fluorothymidine (18F-FLT) positron emission tomography (PET) is used to assess tumor proliferation, since the FLT uptake level reflects thymidine kinase-1 (TK-1) activity. Thus, the present study determined whether FLT was able to evaluate the early tumor response to sorafenib treatment in a human renal cell carcinoma (RCC A498) xenograft in comparison with the tumor proliferation marker, Ki-67. Mice bearing A498 tumors were assigned to the control and sorafenib-treated groups and the tumor volume was measured every day. [Methyl-3H(N)]-3′-fluoro-3′-deoxythymidine (3H-FLT) was injected 2 h prior to the sacrifice of the mice on days three and seven following the treatment. 3H-FLT autoradiography (ARG) and Ki-67 immunohistochemistry (IHC) were performed using tumoral 3H-FLT uptake level diffusely increased following the treatment, while no significant changes were observed in Ki-67 IHC. The intratumoral 3H-FLT uptake levels significantly increased by 2.7- and 2.6-fold on days three and seven following the treatment, while the tumor volume and Ki-67 index did not significantly change. Thus, an increased FLT uptake level was demonstrated following the treatment, which may indicate the suppression of thymidylate synthase (TS) and the compensatory upregulation of TK-1 activity by sorafenib.
• Elevated F-18-FDG Levels in Blood and Organs After Angiotensin II Receptor Blocker Administration: Experiment in Mice Administered Telmisartan

  Yan Zhao, Songji Zhao, Yuji Kuge, Nagara Tamaki

  JOURNAL OF NUCLEAR MEDICINE 54 (8) 1384 - 1388 0161-5505 2013/08 [Refereed][Not invited]
   

  Angiotensin II-receptor blockers (ARBs) are a common treatment for hypertensive patients but affect renal function. In this study, the effects of ARB on F-18-FDG distribution and excretion were examined in mice treated with telmisartan at different doses. Methods: Male C57BL/6J mice were given telmisartan (low-dose group, 0.33 mg/kg/d; moderate-dose group, 0.66 mg/kg/d; high-dose group, 3 mg/kg/d) mixed in a high-fat diet for 20 wk. Mice on a telmisartan-free diet served as the control. At designated time points, the mice were injected with (18)F(-)FDG (18.5 MBq/mouse, n = 5-10/time point for each group) to examine its biodistribution. Autoradiography using kidney sections was performed to visualize F-18-FDG excretion. Plasma blood urea nitrogen (BUN) and creatinine levels were also measured to evaluate renal function. Results: Twenty-week telmisartan treatment significantly and dose-dependently increased F-18-FDG levels in the blood (percentage injected dose per gram of tissue normalized by animal body weight: low, 0.13 +/- 0.03 [P < 0.0083]; moderate, 0.15 +/- 0.01 [P < 0.0083]; high, 0.15 0.03 [P < 0.0083], vs. control, 0.09 +/- 0.01). Significantly increased F-18-FDG levels in organs were observed in mice in the moderate- and high-dose groups but not in the low-dose group. The plasma BUN and creatinine levels also dose-dependently increased, but they were within the reference ranges (for BUN: low, 27.00 +/- 4.42 mg/dL; moderate, 28.40 +/- 2.70 mg/dL; high, 39.22. +/- 6.91 mg/dL [P < 0.0083], vs. control, 22.40 +/- 2.80 mg/dL. For creatinine: low, 0.28 +/- 0.11 mg/dL; moderate, 0.40 +/- 0.07 mg/dL [P < 0.0083]; high, 0.51 +/- 0.09 mg/dL [P < 0.0083], vs. control, 0.18 +/- 0.04 mg/dL). The blood F-18-FDG level positively correlated with plasma BUN (r = 0.48, P < 0.01) and creatinine (r = 0.61, P < 0.01) levels. The F-18-FDG levels in the blood and organs returned to baseline 3 wk after cessation of telmisartan treatment. Autoradiography indicated that renal F-18-FDG excretion was attenuated by telmisartan treatment and was reversed after treatment cessation. Conclusion: F-18-FDG levels in the blood and organs were significantly increased by telmisartan treatment, indicating a potential increase in background activity on PET imaging of patients treated with ARBs. Our findings indicate the need for a careful assessment of F-18-FDG uptake in patients treated with ARBs. A brief cessation of ARB treatment may be a potential method to avoid these effects and solve this problem.
• Radiation-induced nitric oxide mitigates tumor hypoxia and radioresistance in a murine SCCVII tumor model

  Masaki Nagane, Hironobu Yasui, Tohru Yamamori, Songji Zhao, Yuji Kuge, Nagara Tamaki, Hiromi Kameya, Hideo Nakamura, Hirotada Fujii, Osamu Inanami

  BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 437 (3) 420 - 425 0006-291X 2013/08 [Refereed][Not invited]
   

  Tumor hypoxia, which occurs mainly as a result of inadequate tissue perfusion in solid tumors, is a well-known challenge for successful radiotherapy. Recent evidence suggests that ionizing radiation (IR) upregulates nitric oxide (NO) production and that IR-induced NO has the potential to increase intratumoral circulation. However, the kinetics of NO production and the responsible isoforms for NO synthase in tumors exposed to IR remain unclear. In this study, we aimed to elucidate the mechanism by which IR stimulates NO production in tumors and the effect of IR-induced NO on tumor radiosensitivity. Hoechst33342 perfusion assay and electron spin resonance oxymetry showed that IR increased tissue perfusion and pO(2) in tumor tissue. Immunohistochemical analysis using two different hypoxic probes showed that IR decreased hypoxic regions in tumors; treatment with a nitric oxide synthase (NOS) inhibitor, L-NAME, abrogated the effects of IR. Moreover, IR increased endothelial NOS (eNOS) activity without affecting its mRNA or protein expression levels in SCCVII-transplanted tumors. Tumor growth delay assay showed that L-NAME decreased the anti-tumor effect of fractionated radiation (10 Gy x 2). These results suggested that IR increased eNOS activity and subsequent tissue perfusion in tumors. Increases in intratumoral circulation simultaneously decreased tumor hypoxia. As a result, IR-induced NO increased tumor radiosensitivity. Our study provides a new insight into the NO-dependent mechanism for efficient fractionated radiotherapy. (C) 2013 Elsevier Inc. All rights reserved.
• F-18-Fluoromisonidazole PET Uptake Is Correlated with Hypoxia-Inducible Factor-1 alpha Expression in Oral Squamous Cell Carcinoma

  Jun Sato, Yoshimasa Kitagawa, Yutaka Yamazaki, Hironobu Hata, Shozo Okamoto, Tohru Shiga, Masanobu Shindoh, Yuji Kuge, Nagara Tamaki

  JOURNAL OF NUCLEAR MEDICINE 54 (7) 1060 - 1065 0161-5505 2013/07 [Refereed][Not invited]
   

  Hypoxia is a common feature of cancer and a prognostic factor for many types of cancer. F-18-fluoromisonidazole (F-18-FMISO) PET can detect tumor hypoxia noninvasively. Hypoxia-inducible factor-1 (HIF-1) is a key player in the transcriptional response to low oxygen tension in many types of cancer. Its activity is mainly dependent on the stability and modification of HIF-1 alpha, which is a composition of HIF-1. However, it is unclear whether F-18-FMISO PET can identify HIF-1 alpha expression in oral squamous cell carcinoma (OSCC). The present study was performed to elucidate the correlation between F-18-FMISO PET findings and HIF-1 alpha expression in OSCC. Methods: Twenty-three patients (age range, 42-84 y; 15 men, 8 women) with OSCC were enrolled in this study. The T-stages of cancer were T1 in 1 patient, T2 in 9, T3 in 2, and T4a in 11. The N-stages were N0 in 13 patients, N1 in 5, and N2 in 5. Each patient underwent F-18-FMISO and F-18-FDG PET before surgery, and the maximum standardized uptake value (SUVmax) of both PET studies was measured. HIF-1 alpha expression in the operation materials was evaluated by immunohistochemical staining. The SUVmax of both PET studies and HIF-1 alpha findings were compared statistically. Results: F-18-FMISO PET detected uptake in the primary site in 14 of the 23 patients (61%). The median SUVmax of F-18-FMISO and F-18-FDG PET in the primary site was 1.83 (range, 0.8-2.7) and 16.5 (range, 1.0-32.3), respectively. There was a weak significant correlation between F-18-FMISO and F-18-FDG PET SUVmax (P = 0.02, r = 0.48). HIF-1 alpha expression was clearly detected in 11 of the 23 patients (48%). The F-18-FMISO PET SUVmax was significantly higher in the HIF-1 alpha-positive cases than in the HIF-1 alpha-negative cases (median, 2.1; range, 1.5-2.4, vs. median, 1.6; range, 0.8-2.0, respectively) (P = 0.002). However, there were no significant correlations between F-18-FDG PET SUVmax and HIF-1 alpha expression (median, 21.8; range, 7.7-29.1 vs. 1.0-32.2) (P = 0.06). Conclusion: F-18-FMISO uptake in the primary site of OSCC indicates a hypoxic environment with HIF-1 alpha expression.
• Attenuation of Apoptosis by Telmisartan in Atherosclerotic Plaques of Apolipoprotein E-/- Mice: Evaluation Using Technetium 99m-Annexin A5

  Yan Zhao, Songji Zhao, Yuji Kuge, H. William Strauss, Francis G. Blankenberg, Nagara Tamaki

  MOLECULAR IMAGING 12 (5) 300 - 309 1535-3508 2013/07 [Refereed][Not invited]
   

  Technetium 99m (Tc-99m)-annexin A5, a marker of ongoing apoptosis, is supposed to be useful in the detection of metabolically active atheroma. The aim of this study was to determine the potential of Tc-99m-annexin A5 for evaluating the therapeutic effects of an angiotensin II receptor type 1 blocker (ARB) (telmisartan) on atherosclerosis. Male apolipoprotein E (/) mice were divided into telmisartan-treated (3 mg/kg/d, n = 10) and control (n = 10) groups. After 16 to 21 weeks of treatment, Tc-99m-annexin A5 was injected and cryostat sections of aortic tissues (n = 10-12/aorta) were prepared. The Tc-99m-annexin A5 accumulation level in the plaques was evaluated by autoradiography. Serial sections of the plaques were histologically examined to identify the lesion phenotypes (normal vessels, early lesions, atheromatous lesions, and fibrotic lesions), plaque size, macrophage infiltration levels, and lipid deposition levels. Telmisartan treatment significantly decreased the plaque size (0.05 +/- 0.05 vs 0.11 +/- 0.08, mm(2)), macrophage infiltration level (0.02 +/- 0.02 vs 0.03 +/- 0.02, mm(2)), lipid deposition level (0.01 +/- 0.01 vs 0.02 +/- 0.02, mm(2)), and Tc-99m-annexin A5 accumulation level (1.30 +/- 1.09 vs 2.15 +/- 1.91, x 10(-6)/g). Tc-99m-annexin A5 accumulation levels in the plaques positively correlated with macrophage infiltration (r = .69, p < .05) and lipid deposition (r = .66, p < .05) levels. Apoptosis imaging with Tc-99m-annexin A5 may be useful for evaluating the therapeutic effects of ARBs on atherosclerosis.
• Synthesis and evaluation of C-11-labeled naphthalene derivative as a novel non-peptidergic probe for the beta-secretase (BACE1) imaging in Alzheimer's disease brain

  Tomoki Kawai, Hidekazu Kawashima, Yuji Kuge, Hideo Saji

  NUCLEAR MEDICINE AND BIOLOGY 40 (5) 705 - 709 0969-8051 2013/07 [Refereed][Not invited]
   

  Introduction: As a first trial for in vivo imaging of beta-secretase (BACE1) in Alzheimer's disease brain, we applied a novel non-peptidergic small molecule which has high affinity to the enzyme, naphthalene-1-carboxylic acid (3'-chloro-4'-fluoro-4-piperazin-1-yl-biphenyl-3-yl)amide (NCFB) into positron emission tomography (PET) probe. In the current study, N-C-11-methylated compound of NCFB, [C-11]Me-NCFB was synthesized and evaluated for the visualization of BACE1 in brain. Methods: BACE1 inhibitory constant was measured by FRET assay. [C-11]Me-NCFB was synthesized from NCFB with [C-11]methyl triflate. To evaluate properties of [C-11]Me-NCFB, log P value, stability in mouse plasma and brain uptake index were measured. The biodistribution in 6-week-old ddY mice was also studied. Results: BACE1 inhibitory constant showed an affinity of Me-NCFB to the enzyme (IC50 = 2.3 +/- 0.80 mu M). [C-11]Me-NCFB was synthesized in a 3.0% +/- 0.55% decay-corrected radiochemical yield. [C-11]Me-NCFB showed high lipophilicity, high stability in mouse plasma and blood-brain barrier (BBB) permeability. Injected to 6-week-old ddY mice, [C-11]Me-NCFB penetrated BBB and was retained in the brain (0.79% +/- 0.22% ID/g at 2 min and 0.75% +/- 0.08% ID/g at 60 min after injection, respectively), moreover, rapid blood clearance was observed. Conclusion: [C-11]Me-NCFB could have a potential as a PET probe for the imaging of BACE1 in the brain. (C) 2013 Elsevier Inc. All rights reserved.
• Monitoring tumor proliferative response to radiotherapy using F-18-fluorothymidine in human head and neck cancer xenograft in comparison with Ki-67

  Chowdhury Nusrat Fatema, Songji Zhao, Yan Zhao, Masahiro Murakami, Wenwen Yu, Ken-ichi Nishijima, Nagara Tamaki, Yoshimasa Kitagawa, Yuji Kuge

  ANNALS OF NUCLEAR MEDICINE 27 (4) 355 - 362 0914-7187 2013/05 [Refereed][Not invited]
   

  Although radiotherapy is an important treatment strategy for head and neck cancers, it induces tumor repopulation which adversely affects therapeutic outcome. In this regard, fractionated radiotherapy is widely applied to prevent tumor repopulation. Evaluation of tumor proliferative activity using F-18-fluorothymidine (FLT), a noninvasive marker of tumor proliferation, may be useful for determining the optimal timing of and dose in the repetitive irradiation. Thus, to assess the potentials of FLT, we evaluated the sequential changes in intratumoral proliferative activity in head and neck cancer xenografts (FaDu) using FLT. FaDu tumor xenografts were established in nude mice and assigned to control and two radiation-treated groups (10 and 20 Gy). Tumor volume was measured daily. H-3-FLT was injected intravenously 2 h before killing. Mice were killed 6, 24, 48 h, and 7 days after the radiation treatment. Intratumoral H-3-FLT level was visually and quantitatively assessed by autoradiography. Ki-67 immunohistochemistry (IHC) was performed. In radiation-treated mice, the tumor growth was significantly suppressed compared with the control group, but the tumor volume in these mice gradually increased with time. In the visual assessment, intratumoral H-3-FLT level diffusely decreased 6 h after the radiation treatment and then gradually increased with time, whereas no apparent changes were observed in Ki-67 IHC. Six hours after the radiation treatment at 10 and 20 Gy, the intratumoral H-3-FLT level markedly decreased to 45 and 40 % of the control, respectively (P < 0.0001 vs control), and then gradually increased with time. In each radiation-treated group, the H-3-FLT levels at 48 h and on day 7 were significantly higher than that at 6 h. The intratumoral H-3-FLT levels in both treated groups were 68 and 60 % at 24 h (P < 0.001), 71 and 77 % at 48 h (P < 0.001), and 83 and 81 % on day 7 (P = NS) compared with the control group. Intratumoral FLT uptake level markedly decreased at 6 h and then gradually increased with time. Sequential evaluation of intratumoral proliferative activity using FLT can be beneficial for determining the optimal timing of and dose in repetitive irradiation of head and neck cancer.
• Timing and cell dose determine therapeutic effects of bone marrow stromal cell transplantation in rat model of cerebral infarct

  Masahito Kawabori, Satoshi Kuroda, Masaki Ito, Hideo Shichinohe, Kiyohiro Houkin, Yuji Kuge, Nagara Tamaki

  NEUROPATHOLOGY 33 (2) 140 - 148 0919-6544 2013/04 [Refereed][Not invited]
   

  Stereotactic transplantation of bone marrow stromal cells (BMSCs) enables efficient delivery to the infarct brain. This study was aimed to assess its optimal timing and cell dose for ischemic stroke. The BMSCs were harvested from the green fluorescent protein-transgenic rats and were labeled with quantum dots. The BMSCs (1x105 or 1x106) were stereotactically transplanted into the ipsilateral striatum of the rats subjected to permanent middle cerebral artery occlusion at 1 or 4 weeks post-ischemia. Motor function was serially assessed. Using in vivo near infrared (NIR) fluorescence imaging, the engrafted BMSCs were visualized at 3 weeks post-transplantation. Immunohistochemistry was performed to evaluate their fate. Functional recovery was significantly enhanced when both low and high doses of BMSCs were transplanted at 1 week post-ischemia, but such therapeutic effects were observed only when the high-dose BMSCs were transplanted at 4 weeks post-ischemia. Both optical imaging and immunohistochemistry revealed their better engraftment in the peri-infarct area when the high-dose BMSCs were transplanted at 1 or 4 weeks post-ischemia. These findings strongly suggest the importance of timing and cell dose to yield therapeutic effects of BMSC transplantation for ischemic stroke. Earlier transplantation requires a smaller number of donor cells for beneficial effects.
• Biological characteristics of intratumoral [F-18]-fluoromisonidazole distributionin a rodent model of glioma

  Toshiyuki Hatano, Songji Zhao, Yan Zhao, Ken-Ichi Nishijima, Norihito Kuno, Hiroko Hanzawa, Takeshi Sakamoto, Nagara Tamaki, Yuji Kuge

  International Journal of Oncology 42 (3) 823 - 830 1019-6439 2013/03 [Refereed][Not invited]
   

  Accurate imaging to identify hypoxic regions in tumors is key for radiotherapy planning. [F-18]-fluoromisonidazole ([F-18]-FMISO) is widely used for tumor hypoxia imaging and has the potential to optimize radiotherapy planning. However, the biological characteristics of intratumoral [F-18]-FMISO distribution have not yet been fully investigated. In hypoxic cells, the hypoxia-inducible factor-1 (HIF-1) target proteins that induce cellular proliferation and glucose metabolism, glucose transporter-1 (Glut-1) and hexokinase-II (HK-II), are upregulated. In this study, we determined the intratumoral distribution of [F-18]-FMISO by autoradiography (ARG) and compared it with pimonidazole uptake, expression of Glut-1, tumor proliferative activity (Ki-67 index) and glucose metabolism ([C-14]2-fluoro-2-deoxy-D-glucose uptake [C-14]-FDG) in a glioma rat model. Five C6 glioma-bearing rats were injected with [F-18]-FMISO and [C-14]-FDG. After 90 min, the rats were injected with pimonidazole and 60 min later, the rats were sacrificed and tumor tissues were sectioned into slices. The adjacent slices were used for ARG and immunohistochemical (IHC) analyses of pimonidazole, Glut-1 and Ki-67. [F-18]-FMISO ARG images were divided into regions of high [F-18]-FMISO uptake (FMISO+) and low [F-18]-FMISO uptake (FMISO-). Pimonidazole and Glut-1 expression levels, Ki-67 index and [C-14]-FDG distribution were evaluated in the regions of interest (ROIs) placed on FMISO+ and FMISO-. [F-18]-FMISO distribution was generally consistent with pimonidazole distribution. The percentage of positively stained areas (% positive) of Glut-1 in FMISO+ was significantly higher compared to FMISO- (24±8% in FMISO+ and 9±4% in FMISO- P< 0.05). There were no significant differences in Ki-67 index and [C-14]-FDG uptake between FMISO+ and FMISO- (for Ki-67, 10±5% in FMISO+ and 12±5% in FMISO-, P = ns for [C-14]-FDG, 1.4±0.3% ID/g/kg in FMISO+ and 1.3±0.3% ID/g/kg in FMISO-, P = ns). Intratumoral [F-18]-FMISO distribution reflected tumor hypoxia and expression of the hypoxia-related gene product Glut-1 it did not, however, reflect tumor proliferation or glucose metabolism. Our findings help elucidate the biological characteristics of intratumoral [F-18]-FMISO distribution that are relevant to radiotherapy planning.
• High Reproducibility of Tumor Hypoxia Evaluated by F-18-Fluoromisonidazole PET for Head and Neck Cancer

  Shozo Okamoto, Tohru Shiga, Koichi Yasuda, Yoichi M. Ito, Keiichi Magota, Katsuhiko Kasai, Yuji Kuge, Hiroki Shirato, Nagara Tamaki

  JOURNAL OF NUCLEAR MEDICINE 54 (2) 201 - 207 0161-5505 2013/02 [Refereed][Not invited]
   

  Tumor hypoxia is well known to be radiation resistant. F-18-fluoromisonidazole (F-18-FMISO) PET has been used for noninvasive evaluation of hypoxia. Quantitative evaluation of F-18-FMISO uptake is thus expected to play an important role in the planning of dose escalation radiotherapy. However, the reproducibility of F-18-FMISO uptake has remained unclarified. We therefore investigated the reproducibility of tumor hypoxia by using quantitative analysis of F-18-FMISO uptake. Methods: Eleven patients with untreated head and neck cancer underwent 2 F-18-FMISO PET/CT scans (F-18-FMISO1 and F-18-FMISO2) with a 48-h interval prospectively. All images were acquired at 4 h after F-18-FMISO injection for 10 min. The maximum standardized uptake (SUVmax), tumor-to-blood ratio (TBR), and tumor-to-muscle ratio (TMR) of F-18-FMISO uptake were statistically compared between the 2 F-18-FMISO scans by use of intraclass correlation coefficients (ICCs). The hypoxic volume was calculated as the area with a TBR of greater than or equal to 1.5 or the area with a TMR of greater than or equal to 1.25 to assess differences in hypoxic volume between the 2 F-18-FMISO scans. The distances from the maximum uptake locations of the F-18-FMISO1 images to those of the F-18-FMISO2 images were measured to evaluate the locations of F-18-FMISO uptake. Results: The SUVmax (mean +/- SD) for F-18-FMISO1 and F-18-FMISO2 was 3.16 +/- 1.29 and 3.02 +/- 1.12, respectively, with the difference between the 2 scans being 7.0% +/- 4.6%. The TBRs for F-18-FMISO1 and F-18-FMISO2 were 2.98 +/- 0.83 and 2.97 +/- 0.64, respectively, with a difference of 9.9% +/- 3.3%. The TMRs for F-18-FMISO1 and F-18-FMISO2 were 2.25 +/- 0.71 and 2.19 +/- 0.67, respectively, with a difference of 7.1% +/- 5.3%. The ICCs for SUVmax, TBR, and TMR were 0.959, 0.913, and 0.965, respectively. The difference in hypoxic volume based on TBR was 1.8 +/- 1.8 mL, and the difference in hypoxic volume based on TMR was 0.9 +/- 1.3 mL, with ICCs of 0.986 and 0.996, respectively. The maximum uptake locations of the F-18-FMISO1 images were different from those of the F-18-FMISO2 images and were within the full width at half maximum of the PET/CT scanner, except in 1 case. Conclusion: The values for F-18-FMISO PET uptake and hypoxic volume in head and neck tumors between the 2 F-18-FMISO scans were highly reproducible. Such high reproducibility of tumor hypoxia is promising for accurate radiation planning.
• Arterial 18F-Fluorodeoxyglucose uptake reflects balloon catheter-induced thrombus formation and tissue factor expression via nuclear factor-κB in rabbit atherosclerotic lesions

  Atsushi Yamashita, Yan Zhao, Songji Zhao, Yunosuke Matsuura, Chihiro Sugita, Takashi Iwakiri, Nozomi Okuyama, Kazuyo Ohe, Chihiro Koshimoto, Keiichi Kawai, Nagara Tamaki, Yuji Kuge, Yujiro Asada

  Circulation Journal 77 (10) 2626 - 2635 1346-9843 2013 [Refereed][Not invited]
   

  Background: Imaging modalities to assess atherosclerotic plaque thrombogenicity have not been established, so in this study the relationship between [18F]-fluorodeoxyglucose (18F-FDG) uptake and thrombus formation was investigated in rabbit atherosclerotic arteries. Methods and Results: Atherosclerotic plaque was induced in the iliacofemoral artery by balloon injury and a 0.5% cholesterol diet. At 3 weeks after the first balloon injury, the arteries were visualized by 18F-FDG positron emission tomography (PET) imaging 2 h after an 18F-FDG infusion, and then arterial thrombus was induced by a second balloon injury of both iliacofemoral arteries. Imaging with 18F-FDG-PET revealed significantly more radioactivity along the injured (0.63±0.12 SUVmax), than the contralateral non-injured artery (0.34±0.08 SUVmax, n=17, P< 0.0001). Arterial radioactivity measured by autoradiography positively correlated with macrophage area, the number of nuclei that were immunopositive for nuclear factor κ B (NF-κB), and tissue factor (TF) expression. The immunopositive areas for glycoprotein IIb/IIIa and fibrin in thrombi were significantly larger in the atherosclerotic than in the contra-lateral arteries, and significantly correlated with radioactivity in PET (r=0.92, P< 0.001, n=10) and autoradiography (r=0.73, P< 0.0001, n=50) in the arteries. Inhibition of NF-κB significantly reduced TF expression in cultured atherosclerotic plaque. Conclusions: Arterial 18F-FDG uptake reflects the thrombogenicity of atherosclerotic plaque following balloon injury.
• Bone marrow stromal cell transplantation enhances recovery of local glucose metabolism after cerebral infarction in rats: A serial 18F-FDG PET study

  Michiyuki Miyamoto, Satoshi Kuroda, Songji Zhao, Keiichi Magota, Hideo Shichinohe, Kiyohiro Houkin, Yuji Kuge, Nagara Tamaki

  Journal of Nuclear Medicine 54 (1) 145 - 150 0161-5505 2013/01 [Refereed][Not invited]
   

  This study aimed to assess whether 18F-FDG PET could serially monitor the beneficial effects of bone marrow stromal cells (BMSC) on cerebral glucose metabolism when transplanted into the infarct brain of rats. Methods: The BMSC from green fluorescent protein transgenic rats or vehicle was stereotactically transplanted into the ipsilateral striatum at 7 d after permanent middle cerebral artery occlusion of rats. Local glucose metabolism was semiquantitatively measured at 6 and 35 d after ischemia using 18F-FDG PET. Motor function was serially evaluated throughout the experiments. At 35 d after ischemia, immunohistochemistry was performed to evaluate the phenotype of BMSC and their effects on the expression of brain-type glucose transporters. Results: BMSC transplantation not only enhanced functional recovery but also promoted the recovery of glucose utilization in the periinfarct area when stereotactically transplanted at 1 wk after ischemia. The engrafted cells were widely distributed, and most expressed a neuron-specific protein, NeuN. BMSC transplantation also prevented the pathologic upregulation of glucose transporters in the periinfarct neocortex. Conclusion: The present findings strongly suggest that the BMSC may enhance functional recovery by promoting the recovery of local glucose metabolism in the periinfarct area when directly transplanted into the infarct brain at clinically relevant timing. The BMSC also inhibit the pathologic upregulation of brain-isoform glucose transporters type 1 and 3. 18F-FDG PET may be a valuable modality to scientifically prove the beneficial effects of BMSC transplantation on the host brain in clinical situations. COPYRIGHT © 2013 by the Society of Nuclear Medicine and Molecular Imaging, Inc.
• Pathophysiological characteristics of melanoma in-transit metastasis in a lymphedema mouse model

  Kohei Oashi, Hiroshi Furukawa, Hiroshi Nishihara, Michitaka Ozaki, Akihiko Oyama, Emi Funayama, Toshihiko Hayashi, Yuji Kuge, Yuhei Yamamoto

  Journal of Investigative Dermatology 133 (2) 537 - 544 1523-1747 2013 [Refereed][Not invited]
   

  In-transit metastasis (ITM) is a unique manifestation of intralymphatic tumor dissemination, characterized by the presence of melanoma cells between the primary lesion and the draining regional lymph node basin that is clinically associated with poor prognosis. In this study, we aimed to establish an experimental animal model of melanoma ITM, as research progress in this field has been hampered by a lack of suitable experimental models. We reproduced melanoma ITM in a mouse hind limb by transplanting melanoma cells into the footpad of a mouse with lymphedema (LE). The tumor cells at the ITM site were highly proliferative, and mice with ITMs were more likely than control mice to develop distant lymph node and lung metastases. Peritumoral lymphatic vessels and tumor-associated blood vessels were increased in the primary tumor site of the LE mice. Our established ITM melanoma mouse model enabled us to clarify the molecular determinants and pathophysiology of ITM. This ITM model is also comparable to the unfavorable clinical behavior of melanoma ITM in humans and, moreover, underlined the importance of lymphangiogenic factors in the tumor dissemination through the lymphatic system. © 2013 The Society for Investigative Dermatology.
• [(18)F]fluoromisonidazole and a New PET System With Semiconductor Detectors and a Depth of Interaction System for Intensity Modulated Radiation Therapy for Nasopharyngeal Cancer.

  Yasuda K, Onimaru R, Okamoto S, Shiga T, Katoh N, Tsuchiya K, Suzuki R, Takeuchi W, Kuge Y, Tamaki N, Shirato H

  Int J Radiat Oncol Biol Phys. 85 (1) 142 - 7 2013 [Refereed][Not invited]
  
• Ferrous Ferric Chloride Downregulates the Inflammatory Response to Rhodococcus aurantiacus Infection in Mice

  Yimin, Huirong Tao, Masashi Kohanawa, Songji Zhao, Yuji Kuge, Nagara Tamaki

  BIOLOGICAL & PHARMACEUTICAL BULLETIN 35 (12) 2214 - 2223 0918-6158 2012/12 [Refereed][Not invited]
   

  The healthy drink Pairogen is mainly composed of ferrous ferric chloride water that reportedly changes the status of intracellular water from oxidative to antioxidative. Here, we investigated whether Pairogen affects host immune function in a murine model of granulomatous inflammation in response to Rhodococcus aurantiacus (R. aurantiacus) infection. Longitudinal ingestion of Pairogen markedly improved the survival of infected mice in a concentration-dependent manner. Compared to mice received water, mice that ingested 10-fold-diluted Pairogen displayed rapid bacterial elimination, decreased production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6, and high levels of IL-10 in organs during the initial phase of infection. Moreover, histological studies showed significant reduction in the number and size of granulomas as well as amelioration of oxidative stress in the livers of mice ingested 10-fold-diluted Pairogen at 14d post-infection. These characteristics were further pronounced in first-generation (F1) mice that also ingested 10-fold-diluted Pairogen. Following stimulation with heat-killed R. aurantiacus, the production of TNF-alpha, IL-6, and IL-10 by macrophages from F1 mice was similar to that detected in vivo, while their gene expression levels in these cells were significantly lower than the levels in macrophages from mice received water. Heat-killed R. aurantiacus also induced the expression of heme oxygenase-1 mRNA in the cells from F1 mice. Taken together, these results indicate that Pairogen contributes to the negative regulation of the immuno-inflammatory response to R. aurantiacus infection in mice by modulating the cellular redox state. Longitudinal ingestion of Pairogen further enhances the defense function in mouse progeny.
• (11)C-Methionine positron emission tomography may monitor the activity of encephalitis.

  Kenji Hirata, Tohru Shiga, Noriyuki Fujima, Osamu Manabe, Reiko Usui, Yuji Kuge, Nagara Tamaki

  Acta radiologica (Stockholm, Sweden : 1987) 53 (10) 1155 - 7 2012/12/01 [Refereed][Not invited]
   

  Encephalitis is generally diagnosed by clinical symptoms, cerebrospinal fluid examination, and imaging studies including CT, magnetic resonance imaging (MRI), and perfusion single photon emission tomography (SPECT). However, the role of positron emission tomography (PET) in diagnosis of encephalitis remains unclear. A 49-year-old woman presenting with coma and elevated inflammatory reaction was diagnosed as having encephalitis according to slow activity on electroencephalogram, broad cortical lesion in MR fluid attenuated inversion recovery image, and increased blood flow demonstrated by SPECT. PET revealed increased accumulation of (11)C-methionine (MET) in the affected brain tissues. After the symptom had improved 2 months later, the accumulation of MET as well as the abnormal findings of MR imaging and SPECT was normalized. This case indicated that MET PET may monitor the activity of encephalitis.
• Evaluation of changes in the tumor microenvironment after sorafenib therapy by sequential histology and F-18-fluoromisonidazole hypoxia imaging in renal cell carcinoma

  Masahiro Murakami, Songji Zhao, Yan Zhao, Nusrat Fatema Chowdhury, Wenwen Yu, Ken-Ichi Nishijima, Mitsuyoshi Takiguchi, Nagara Tamaki, Yuji Kuge

  INTERNATIONAL JOURNAL OF ONCOLOGY 41 (5) 1593 - 1600 1019-6439 2012/11 [Refereed][Not invited]
   

  The mechanistic dissociation of 'tumor starvation' versus 'vascular normalization' following anti-angiogenic therapy is a subject of intense controversy in the field of experimental research. In addition, accurately evaluating changes of the tumor microenvironment after anti-angiogenic therapy is important for optimizing treatment strategy. Sorafenib has considerable anti-angiogenic effects that lead to tumor starvation and induce tumor hypoxia in the highly vascularized renal cell carcinoma (RCC) xenografts. F-18-fluoromisonidazole (F-18-FMISO) is a proven hypoxia imaging probe. Thus, to clarify early changes in the tumor microenvironment following anti-angiogenic therapy and whether F-18-FMISO imaging can detect those changes, we evaluated early changes in the tumor microenvironment after sorafenib treatment in an RCC xenograft by sequential histological analysis and F-18-FMISO autoradiography (ARG). A human RCC xenograft (A498) was established in nude mice, for histological studies and ARG, and further assigned to the control and sorafenib-treated groups (80 mg/kg, per os). Mice were sacrificed on Days 1, 2, 3 and 7 in the histological study, and on Days 3 and 7 in ARG after sorafenib treatment. Tumor volume was measured every day. F-18-FMISO and pimonidazole were injected intravenously 4 and 2 h before sacrifice, respectively. Tumor sections were stained with hematoxylin and eosin and immunohistochemically with pimonidazole and CD31. Intratumoral F-18-FMISO distribution was quantified in ARG. Tumor volume did not significantly change on Day 7 after sorafenib treatment. In the histological study, hypoxic fraction significantly increased on Day 2, mean vessel density significantly decreased on Day 1 and necrosis area significantly increased on Day 2 after sorafenib treatment. Intratumoral F-18-FMISO distribution significantly increased on Days 3 (10.2-fold, p<0.01) and 7 (4.1-fold, p<0.01) after sorafenib treatment. The sequential histological evaluation of the tumor microenvironment clarified tumor starvation in A498 xenografts treated with sorafenib. F-18-FMISO hypoxia imaging confirmed the tumor starvation. F-18-FMISO PET may contribute to determine an optimum treatment protocol after anti-angiogenic therapy.
• Quantitative Determination of Apoptosis of Pancreatic beta-Cells in a Murine Model of Type 1 Diabetes Mellitus

  Ayahisa Watanabe, Ken-ichi Nishijima, Songji Zhao, Yan Zhao, Yoshikazu Tanaka, Hiroshi Takemoto, H. William Strauss, Francis G. Blankenberg, Nagara Tamaki, Yuji Kuge

  JOURNAL OF NUCLEAR MEDICINE 53 (10) 1585 - 1591 0161-5505 2012/10 [Refereed][Not invited]
   

  Type 1 diabetes mellitus is characterized by a significant deficit in pancreatic beta-cell mass, presumably caused by beta-cell apoptosis. We investigated the incidence of beta-cell apoptosis in streptozotocin-treated mice and nonobese diabetic (NOD) mice with Tc-99m-annexin A5. Methods: Vehicle-treated mice, streptozotocin-treated mice, and NOD mice at the ages of 5, 9, 16, and 20 wk (5-8 mice per group) were injected with Tc-99m-annexin A5 and sacrificed 6 h later for autoradiography, and the regional Tc-99m-annexin A5 level in the pancreas was evaluated. Pancreatic islets were identified by insulin immunohistochemical staining, and apoptotic cells were determined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining. The Tc-99m-annexin A5 level in pancreatic islets was expressed as the percentage injected dose per area of pancreatic islets and normalized by animal body weight (%ID x 10(6)/mm(2)/kg). The level of apoptotic cells in pancreatic islets was expressed as the number of TUNEL-positive cells per area of pancreatic islets (cells/mm(2)). Results: The Tc-99m-annexin A5 accumulation level was significantly higher (2.5 +/- 0.7 vs. 0.7 +/- 0.1 %ID x 106/mm(2)/kg, P < 0.05) and the number of TUNEL-positive cells was significantly higher (1,170 +/- 535 vs. 5 6 cells/mm(2), P < 0.05) in the pancreatic islets of the streptozotocin-treated mice than in those of the vehicle-treated mice. The Tc-99m-annexin A5 accumulation level was significantly higher (1.1 +/- 0.4 vs. 0.5 +/- 0.1 %ID x 10(6)/mm(2)/kg, P < 0.05) and the number of TUNEL-positive cells was significantly higher (152 +/- 82 vs. 4 +/- 9 cells/mm(2), P < 0.05) in the pancreatic islets of 16-wk-old NOD mice than in those of 5-wk-old NOD mice. In addition, the level of Tc-99m-annexin AS correlated with the number of TUNEL-positive cells in the pancreatic islets of the streptozotocin-treated mice (r = 0.821, P < 0.001) and NOD mice (r = 0.721, P < 0.001). Conclusion: There is significant islet cell apoptosis with Tc-99m-annexin A5 accumulation in the pancreas of both streptozotocin and NOD mice.
• Cardiac beta-adrenergic receptor density and myocardial systolic function in the remote noninfarcted region after prior myocardial infarction with left ventricular remodelling

  Nobuyuki Ohte, Hitomi Narita, Akihiko Iida, Hidekatsu Fukuta, Narushi Iizuka, Junichiro Hayano, Yuji Kuge, Nagara Tamaki, Genjiro Kimura

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 39 (8) 1246 - 1253 1619-7070 2012/08 [Refereed][Not invited]
   

  After myocardial infarction (MI), left ventricular (LV) remodelling is observed in noninfarcted LV myocardium. LV remodelling is closely associated with systolic heart failure. Since myocardial dysfunction is related to the downregulation of cardiac postsynaptic beta-adrenergic receptors (beta-AR), we hypothesized that a reduction in beta-AR density may be manifested in the remote noninfarcted region and such reduction may be related to myocardial systolic dysfunction. Accordingly, we assessed beta-AR density with a focus on the remote noninfarcted region. Cardiac PET was performed in 15 patients with a prior MI and 10 age-matched healthy controls using C-11-CGP 12177, a radioligand for beta-receptors. The maximum number of available specific C-11-CGP 12177 binding sites per gram of tissue was calculated in regions of interest using an established graphical method. LV regional systolic function was assessed based on peak systolic myocardial strain on the LV wall in the longitudinal direction using two-dimensional ultrasound speckle tracking imaging. LV volumes and LV ejection fraction (EF) were also measured. The LV end-diastolic volume index was significantly larger in patients than in controls (67.8 +/- 16.9 vs. 49.1 +/- 12.3 ml/m(2), p < 0.01). Significant differences in beta-AR density were observed among three areas: the apical area in controls (where the lowest beta-AR density was observed), the remote noninfarcted region of patients and LVEF a parts per thousand yen55 %, and the remote noninfarcted region of patients and LVEF < 55 % (5.8 +/- 2.1 vs. 4.2 +/- 0.7 vs. 3.3 +/- 0.7 pmol/ml, p < 0.01, ANOVA). Peak systolic myocardial strain was significantly reduced in the remote noninfarcted LV wall in patients with a prior anterior wall MI compared with that in the corresponding wall in controls (-15.5 +/- 2.5 vs. -20.1 +/- 2.2 %, p < 0.001). A similar finding was also observed in patients with a prior inferior wall MI. In the remote noninfarcted region in patients, beta-AR downregulation was observed, which was related to deterioration of local myocardial systolic function.
• Norepinephrine Transporter Imaging in the Brain of a Rat Model of Depression Using Radioiodinated (2S, alpha S)-2-(alpha-(2-iodophenoxy)benzyl)morpholine

  Naoki Kanegawa, Yasushi Kiyono, Taku Sugitaa, Yuji Kuge, Yasushisa Fujibayasi, Hideo Saji

  MOLECULAR IMAGING 11 (4) 280 - 285 1535-3508 2012/07 [Refereed][Not invited]
   

  To visualize the norepinephrine transporters (NETs) in various brain diseases, we developed radioiodinated (2S,alpha S)-2-(alpha-(2-iodophenoxy)benzyl) morpholine ((S,S)-IPBM). This radioligand achieved the basic requirements for NET imaging. In this study, we assessed the potential of radioiodinated (S,S)-IPBM as an imaging biomarker of NET to obtain diagnostic information about depression in relation to NET expression in the brain using a rat depression model. The ex vivo autoradiographic experiments using the (S,S)[[I-125]IPBM showed significantly lower accumulation of radioactivity in the locus coeruleus (LC) and the anteroventricular thalamic nucleus (AVTN) of the depression group than in those of the control group. Consequently, in vitro autoradiographic experiments showed that NET maximum binding (B-max) values in the LC and AVTN, known as NET-rich regions, were significantly decreased in the rat model of depression when compared to those of the control rats. In addition, there was an extremely good correlation between NET B-max and (S,S)-IPBM accumulation (r = .98), an indication of radioiodinated IPBM as a quantitative NET imaging biomarker. The reduction in (S,S)-[I-125]IPBM accumulation in the rat model of depression correlated with that of NET density. These results suggest that (S,S)-[I-123]IPBM has potential as an imaging biomarker of NET to obtain diagnostic information about major depression.
• Intracerebral, but not intravenous, transplantation of bone marrow stromal cells enhances functional recovery in rat cerebral infarct: An optical imaging study

  Masahito Kawabori, Satoshi Kuroda, Taku Sugiyama, Masaki Ito, Hideo Shichinohe, Kiyohiro Houkin, Yuji Kuge, Nagara Tamaki

  NEUROPATHOLOGY 32 (3) 217 - 226 0919-6544 2012/06 [Refereed][Not invited]
   

  Recent studies have indicated that bone marrow stromal cells (BMSC) may improve neurological function when transplanted into an animal model of CNS disorders, including cerebral infarct. However, there are few studies that evaluate the therapeutic benefits of intracerebral and intravenous BMSC transplantation for cerebral infarct. This study was aimed to clarify the favorable route of cell delivery for cerebral infarct in rats. The rats were subjected to permanent middle cerebral artery occlusion. The BMSC were labeled with near infrared (NIR)-emitting quantum dots and were transplanted stereotactically (1 x 10(6) cells) or intravenously (3 x 10(6) cells) at 7 days after the insult. Using in vivo NIR fluorescence imaging technique, the behaviors of BMSC were serially visualized during 4 weeks after transplantation. Motor function was also assessed. Immunohistochemistry was performed to evaluate the fate of the engrafted BMSC. Intracerebral, but not intravenous, transplantation of BMSC significantly enhanced functional recovery. In vivo NIR fluorescence imaging could clearly visualize their migration toward the cerebral infarct during 4 weeks after transplantation in the intracerebral group, but not in the intravenous, group. The BMSC were widely distributed in the ischemic brain and some of them expressed neural cell markers in the intracerebral group, but not in the intravenous group. These findings strongly suggest that intravenous administration of BMSC has limited effectiveness at clinically relevant timing and intracerebral administration should be chosen for patients with ischemic stroke, although further studies would be warranted to establish the treatment protocol.
• F-18-Fluoromisonidazole positron emission tomography may differentiate glioblastoma multiforme from less malignant gliomas

  Kenji Hirata, Shunsuke Terasaka, Tohru Shiga, Naoya Hattori, Keiichi Magota, Hiroyuki Kobayashi, Shigeru Yamaguchi, Kiyohiro Houkin, Shinya Tanaka, Yuji Kuge, Nagara Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 39 (5) 760 - 770 1619-7070 2012/05 [Refereed][Not invited]
   

  Purpose Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor and its prognosis is significantly poorer than those of less malignant gliomas. Pathologically, necrosis is one of the most important characteristics that differentiate GBM from lower grade gliomas; therefore, we hypothesized that F-18 fluoromisonidazole (FMISO), a radiotracer for hypoxia imaging, accumulates in GBM but not in lower grade gliomas. We aimed to evaluate the diagnostic value of FMISO positron emission tomography (PET) for the differential diagnosis of GBM from lower grade gliomas. Methods This prospective study included 23 patients with pathologically confirmed gliomas. All of the patients underwent FMISO PET and 18F-fluorodeoxyglucose (FDG) PET within a week. FMISO images were acquired 4 h after intravenous administration of 400 MBq of FMISO. Tracer uptake in the tumor was visually assessed. Lesion to normal tissue ratios and FMISO uptake volume were calculated. Results Of the 23 glioma patients, 14 were diagnosed as having GBM (grade IV glioma in the 2007 WHO classification), and the others were diagnosed as having non-GBM (5 grade III and 4 grade II). In visual assessment, all GBM patients showed FMISO uptake in the tumor greater than that in the surrounding brain tissues, whereas all the non-GBM patients showed FMISO uptake in the tumor equal to that in the surrounding brain tissues (p <= 0.001). One GBM patient was excluded from FDG PET study because of hyperglycemia. All GBM patients and three of the nine (33%) non-GBM patients showed FDG uptake greater than or equal to that in the gray matter. The sensitivity and specificity for diagnosing GBM were 100 and 100% for FMISO, and 100 and 66% for FDG, respectively. The lesion to cerebellum ratio of FMISO uptake was higher in GBM patients (2.74 +/- 0.60, range 1.71-3.81) than in non-GBM patients (1.22 +/- 0.06, range 1.09-1.29, p <= 0.001) with no overlap between the groups. The lesion to gray matter ratio of FDG was also higher in GBM patients (1.46 +/- 0.75, range 0.91-3.79) than in non-GBM patients (1.07 +/- 0.62, range 0.66-2.95, p <= 0.05); however, overlap of the ranges did not allow clear differentiation between GBM and non-GBM. The uptake volume of FMISO was larger in GBM ( 27.18 +/- 10.46%, range 14.02- 46.67%) than in non- GBM ( 6.07 +/- 2.50%, range 2.12- 9.22%, p <= 0.001). Conclusion These preliminary data suggest that FMISO PET may distinguish GBM from lower grade gliomas.
• Writing errors in ALS related to loss of neuronal integrity in the anterior cingulate gyrus

  Ichiro Yabe, Sachiko Tsuji-Akimoto, Tohru Shiga, Shinsuke Hamada, Kenji Hirata, Mika Otsuki, Yuji Kuge, Nagara Tamaki, Hidenao Sasaki

  JOURNAL OF THE NEUROLOGICAL SCIENCES 315 (1-2) 55 - 59 0022-510X 2012/04 [Refereed][Not invited]
   

  Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by loss of motor neuron and various cognitive deficits including writing errors. C-11-flumazenil (FMZ), the positron emission tomography (PET) GABA(A) receptor ligand, is a marker of cortical dysfunction. The objective of this study was to investigate the relationship between cognitive deficits and loss of neuronal integrity in ALS patients using C-11-FMZ PET. Ten patients with ALS underwent both neuropsychological tests and C-11-FMZ-PET. The binding potential (BP) of FMZ was calculated from C-11-FMZ PET images. There were no significant correlations between the BP and most test scores except for the writing error index (WEI), which was measured by the modified Western Aphasia Battery - VB (WAB-IVB) test. The severity of writing error was associated with loss of neuronal integrity in the bilateral anterior cingulate gyrus with mild right predominance (n = 9; x = 4 mm, y = 36 mm, z = 4 mm, Z = 5.1). The results showed that writing errors in our patients with ALS were related to dysfunction in the anterior cingulate gyrus. (c) 2011 Elsevier B.V. All rights reserved.
• Therapeutic effects of intra-arterial delivery of bone marrow stromal cells in traumatic brain injury of rats--in vivo cell tracking study by near-infrared fluorescence imaging.

  Toshiya Osanai, Satoshi Kuroda, Taku Sugiyama, Masahito Kawabori, Masaki Ito, Hideo Shichinohe, Yuji Kuge, Kiyohiro Houkin, Nagara Tamaki, Yoshinobu Iwasaki

  Neurosurgery 70 (2) 435 - 44 2012/02 [Refereed][Not invited]
   

  BACKGROUND: A noninvasive and effective route of cell delivery should be established to yield maximal therapeutic effects for central nervous system (CNS) disorders. OBJECTIVE: To elucidate whether intra-arterial delivery of bone marrow stromal cells (BMSCs) significantly promotes functional recovery in traumatic brain injury (TBI) in rats. METHODS: Rat BMSCs were transplanted through the ipsilateral internal carotid artery 7 days after the onset of cortical freezing injury. The BMSCs were labeled with fluorescent dye, and in vivo optical imaging was employed to monitor the behaviors of cells for 4 weeks after transplantation. Motor function was assessed for 4 weeks, and the transplanted BMSCs were examined using immunohistochemistry. RESULTS: In vivo optical imaging and histologic analysis clearly demonstrated that the intra-arterially injected BMSCs were engrafted during the first pass without systemic circulation, and the transplanted BMSCs started to migrate from the cerebral capillary bed to the injured CNS tissue within 3 hours. Intra-arterial BMSC transplantation significantly promoted functional recovery after cortical freezing injury. A subgroup of BMSCs expressed the phenotypes of neurons, astrocytes, and endothelial cells around the injured neocortex 4 weeks after transplantation. CONCLUSION: Intra-arterial transplantation may be a valuable option for prompt, noninvasive delivery of BMSCs to the injured CNS tissue, enhancing functional recovery after TBI. In vivo optical imaging may provide important information on the intracerebral behaviors of donor cells by noninvasive, serial visualization.
• A novel murine model for non-alcoholic steatohepatitis developed by combination of a high-fat diet and oxidized low-density lipoprotein

  Yin Lin, Hiroaki Furumaki, Shiho Matsuoka, Toshihiro Sakurai, Masashi Kohanawa, Songji Zhao, Yuji Kuge, Nagara Tamaki, Hitoshi Chiba

  LABORATORY INVESTIGATION 92 (2) 265 - 281 0023-6837 2012/02 [Refereed][Not invited]
   

  Not-alcoholic steatohepatitis (NASH) is the hepatic manifestation of metabolic syndrome that is characterized by steritosis, inflammation, and fibrosis, and may progress to cirrhosis and carcinoma. To investigate its pathogenic processes, we established a novel murine model for NASH by combination of a high-fat diet (HFD) and oxidized low-density lipoprotein (oxLDL). Mice that received HFD for 23 weeks showed hepatic steatosis, slight fibrosis, and a high level of lipid peroxidation compared with a regular diet (RD)-fed mice. Hepatic injury and elevated tumor necrosis factoor (TNF)-alpha mRNA expression were also detected in these mice. Moreover, oxLDL administration to HFD-fed mice during weeks 21-23 not only aggravated hepatic steatosis, fibrosis, and lipid metabolism, but also resulted in intense inflammation, including severe hepatic injury and inflammatory cell infiltration, which are the typical histological features of NASH. Inflammation was accompanied by increased gene expression of TNF-alpha and interleukin (IL)-6. Additionally, the livers of RD-fed animals treated with oxLDL during weeks 21-23 were characterized by foamy macrophages and inflammatory cell infiltration along with an elevated IL-6 mRNA level. These results suggest that an increased oxidative state, including HFD-induced intracellular lipid peroxidation and its extracellular source from oxLDL, is the actual trigger for hepatic inflammation in which liver injury is mediated by TNF-alpha: and inflammatory cell accumulation is dependent on HFD and oxLDL also induced insulin resistance in mice; additionally, oxLDL downregulated insulin secretion. In his model, CD36 overexpression was observed in the hepatocytes of HFD-fed mice and those treated with HFD and oxl DL, and in the hepatic macrophages of RD-fed mice immediately after oxLDL treatment. In vitro experiments indicated a rapid and transient elevation of CD36 on macrophage plasma membrane in response to oxLDL. Our findings demonstrate that CD36 expressed on hepatocytes and hepatic macrophages mediates the pathophysiology of NASH. Laboratory Investigation (2012) 92, 265-281; doi:10.1038/labinvest.2011.159; published online 7 November 2011
• Effect of glycosylation on biodistribution of radiolabeled glucagon-like peptide 1

  Ayahisa Watanabe, Ken-ichi Nishijima, Songji Zhao, Yoshikazu Tanaka, Takeshi Itoh, Hiroshi Takemoto, Nagara Tamaki, Yuji Kuge

  ANNALS OF NUCLEAR MEDICINE 26 (2) 184 - 191 0914-7187 2012/02 [Refereed][Not invited]
   

  Glycosylation is generally applicable as a strategy for increasing the activity of bioactive proteins. In this study, we examined the effect of glycosylation on biodistribution of radiolabeled glucagon-like peptide 1 (GLP-1) as a bioactive peptide for type 2 diabetes. Noninvasive imaging studies were performed using a gamma camera after the intravenous administration of I-123-GLP-1 or I-123-alpha 2, 6-sialyl N-acetyllactosamine (glycosylated) GLP-1 in rats. In ex vivo biodistribution studies using I-125-GLP-1 or I-125-glycosylated GLP-1, organ samples were measured for radioactivity. Plasma samples were added to 15% trichloroacetic acid (TCA) to obtain TCA-insoluble and TCA-soluble fractions. The radioactivity in the TCA-insoluble and TCA-soluble fractions was measured. In the noninvasive imaging studies, a relatively high accumulation level of I-123-GLP-1 was found in the liver, which is the major organ to eliminate exogenous GLP-1. The area under the time-activity curve (AUC) of I-123-glycosylated GLP-1 in the liver was significantly lower (89%) than that of I-123-GLP-1. These results were consistent with those of ex vivo biodistribution studies using I-125-labeled peptides. The AUC of I-125-glycosylated GLP-1 in the TCA-insoluble fraction was significantly higher (1.7-fold) than that of GLP-1. This study demonstrated that glycosylation significantly decreased the distribution of radiolabeled GLP-1 into the liver and increased the concentration of radiolabeled GLP-1 in plasma. These results suggested that glycosylation is a useful strategy for decreasing the distribution into the liver of bioactive peptides as desirable pharmaceuticals.
• A Pre-targeting Strategy for MR Imaging of Functional Molecules Using Dendritic Gd-Based Contrast Agents

  Kohei Sano, Takashi Temma, Takashi Azuma, Ryusuke Nakai, Michiko Narazaki, Yuji Kuge, Hideo Saji

  MOLECULAR IMAGING AND BIOLOGY 13 (6) 1196 - 1203 1536-1632 2011/12 [Refereed][Not invited]
   

  Purpose: We aimed to establish a magnetic resonance imaging (MRI) protocol for the sensitive and specific imaging of functional molecules with a pre-targeting strategy utilizing the streptavidin-biotin interaction. Membrane type-1 matrix metalloproteinase (MT1-MMP) was selected as the target molecule. Procedures: The biotinylated polyamidoamine dendrimer (PAMAM)-based contrast agent (Bt-PAMAM-DTPA(Gd)) was prepared, and its proton relaxivity (r1) and affinity to streptavidin were evaluated. Tumor-bearing mice were pre-targeted with streptavidin-conjugated anti-MT1-MMP monoclonal antibody (mAb), streptavidin-conjugated negative control IgG, or saline and 3 days later were injected with Bt-PAMAM-DTPA(Gd) followed immediately by MRI for a period of 3 h. Results: High r1 (15.5 L mmol(-1) s(-1)) and 1.9-fold higher affinity than d-biotin were obtained. Significantly higher relative tumor signals were observed in mice pre-targeted with streptavidin-conjugated anti-MT1-MMP mAb (165% at 3 h vs. pre-administration) than with saline or streptavidin-conjugated negative control IgG (P < 0.0001). Conclusions: This pre-targeting approach can accomplish sensitive and specific in vivo MRI of functional molecules.
• Radiolabeled uracil derivative as a novel SPECT probe for thymidine phosphorylase: suppressed accumulation into tumor cells by target gene knockdown

  Hua Li, Songji Zhao, Yongnan Jin, Ken-ichi Nishijima, Hiromichi Akizawa, Kazue Ohkura, Nagara Tamaki, Yuji Kuge

  NUCLEAR MEDICINE COMMUNICATIONS 32 (12) 1211 - 1215 0143-3636 2011/12 [Refereed][Not invited]
   

  Objectives We have developed a radiolabeled uracil derivative, 5-iodo-6-[(2-iminoimidazolidinyl)methyl]uracil (IIMU) as a novel single photon emission computed tomography probe for thymidine phosphorylase (TP). This radioiodinated IIMU has a high affinity for TP and highly accumulates in the TP-expressing tumor cell line A431 (human epidermoid carcinoma). To evaluate the specificity of the cellular uptake of IIMU to TP expression, we examined the effects of TP knockdown on the uptake of (125)I-labeled IIMU ((125)I-IIMU) in the tumor cells. Methods TP-specific small interfering RNA (siRNA), glyceraldehyde-3-phosphate dehydrogenase (GAPDH)-specific siRNA (positive control), and negative control siRNA were transfected into A431 cells, respectively. Target-mRNA and protein expression levels of TP and GAPDH were examined 48 and 72 h after transfection, respectively. The cellular uptake level of (125)I-IIMU was also evaluated 72 h after transfection. The results were compared after normalization with the corresponding negative controls. Results After TP-specific and GAPDH-specific siRNA transfection, the expression levels of TP and GAPDH mRNA decreased significantly to 41 and 29%, respectively, compared with the negative control (P < 0.001 for both). The expression levels of TP and GAPDH protein also significantly decreased to 34 and 30%, respectively (P < 0.001 for both). After TP-specific siRNA transfection, the cellular uptake level of (125)I-IIMU decreased significantly to 66% (P < 0.001). In contrast, GAPDH siRNA transfection did not significantly affect the cellular uptake level of (125)I-IIMU. Conclusion siRNA-mediated TP knockdown significantly decreased the cellular uptake level of (125)I-IIMU. This finding indicates that the uptake of IIMU in tumor cells is TP specific and directly corresponds to TP expression levels. Nucl Med Commun 32: 1211-1215 (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins. Nuclear Medicine Communications 2011, 32: 1211-1215
• Dynamic C-11-methionine PET analysis has an additional value for differentiating malignant tumors from granulomas: an experimental study using small animal PET

  Songji Zhao, Yuji Kuge, Min Yi, Yan Zhao, Toshiyuki Hatano, Keiichi Magota, Ken-ichi Nishijima, Masashi Kohanawa, Nagara Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 38 (10) 1876 - 1886 1619-7070 2011/10 [Refereed][Not invited]
   

  We evaluated whether the dynamic profile of L-C-11-methionine (C-11-MET) may have an additional value in differentiating malignant tumors from granulomas in experimental rat models by small animal positron emission tomography (PET). Rhodococcus aurantiacus and allogenic rat C6 glioma cells were inoculated, respectively, into the right and left calf muscles to generate a rat model bearing both granulomas and tumors (n = 6). Ten days after the inoculations, dynamic C-11-MET PET was performed by small animal PET up to 120 min after injection of C-11-MET. The next day, after overnight fasting, the rats were injected with F-18-2-deoxy-2-fluoro-D-glucose (F-18-FDG), and dynamic F-18-FDG PET was performed up to 180 min. The time-activity curves, static images, and mean standardized uptake value (SUV) in the lesions were calculated. C-11-MET uptake in the granuloma showed a slow exponential clearance after an initial distribution, while the uptake in the tumor gradually increased with time. The dynamic pattern of C-11-MET uptake in the granuloma was significantly different from that in the tumor (p < 0.001). In the static analysis of C-11-MET, visual assessment and SUV analysis could not differentiate the tumor from the granuloma in all cases, although the mean SUV in the granuloma (1.48 +/- 0.09) was significantly lower than that in the tumor (1.72 +/- 0.18, p < 0.01). The dynamic patterns, static images, and mean SUVs of F-18-FDG in the granuloma were similar to those in the tumor (p = NS). Dynamic C-11-MET PET has an additional value for differentiating malignant tumors from granulomatous lesions, which deserves further elucidation in clinical settings.
• PET Imaging of Hypoxia-Inducible Factor-1-Active Tumor Cells with Pretargeted Oxygen-Dependent Degradable Streptavidin and a Novel F-18-Labeled Biotin Derivative

  Takashi Kudo, Masashi Ueda, Hiroaki Konishi, Hidekazu Kawashima, Yuji Kuge, Takahiro Mukai, Azusa Miyano, Shotaro Tanaka, Shinae Kizaka-Kondoh, Masahiro Hiraoka, Hideo Saji

  MOLECULAR IMAGING AND BIOLOGY 13 (5) 1003 - 1010 1536-1632 2011/10 [Refereed][Not invited]
   

  We aimed to evaluate the feasibility of using streptavidin-biotin-based pretargeting for positron emission tomography (PET) imaging of hypoxia-inducible factor (HIF)-1-active tumors. We used POS, a genetically engineered form of streptavidin that selectively stabilizes in HIF-1-active cells, and (4-F-18-fluorobenzoyl)norbiotinamide (F-18-FBB), a radiolabeled biotin derivative, for performing a biodistribution study and for PET imaging. The tumoral F-18-FBB accumulation was compared to the HIF-1-dependent luciferase bioluminescence and HIF-1 alpha immunohistochemical signal. F-18-FBB accumulation was observed in POS-pretargeted tumors in mice (2.85 +/- 0.55% injected dose per gram at 3 h), and clear PET images were obtained at the same time point. The tumoral F-18-FBB accumulation positively correlated with luciferase bioluminescence (R = 0.72, P < 0.05), and most of the area showing F-18-FBB accumulation corresponded to HIF-1 alpha-positive areas. Pretargeting with POS and F-18-FBB is an effective approach for PET imaging of HIF-1-active areas in tumors.
• F-18-Fluorothymidine PET/CT as an early predictor of tumor response to treatment with cetuximab in human lung cancer xenografts

  Satoshi Takeuchi, Songji Zhao, Yuji Kuge, Yan Zhao, Ken-Ichi Nishijima, Toshiyuki Hatano, Yasushi Shimizu, Ichiro Kinoshita, Nagara Tamaki, Hirotoshi Dosaka-Akita

  ONCOLOGY REPORTS 26 (3) 725 - 730 1021-335X 2011/09 [Refereed][Not invited]
   

  We investigated whether F-18-fluorothymidine-positron-emission tomography/computed tomography (F-18-FLT-PET/CT) is useful for the evaluation of the very early response to anti-epidermal growth factor receptor (EGFR) antibody cetuximab therapy in human lung cancer xenografts. A human tumor xenograft model was established with a human non-small cell lung cancer cell line. The mice were randomly assigned to four groups: tumor growth follow-up, ex vivo study, PET/CT imaging and non-treated control. Mice were administered saline as control or cetuximab on day 1. An immunohistochemical study with Ki-67 was performed. Tumor volume treated with cetuximab was kept significantly smaller than control after day 8, although there was no difference on day 3. On day 3, F-18-FLT distribution was higher in the tumor than in other tissues, and was significantly decreased by treatment with cetuximab. On PET/CT imaging, F-18-FLT distribution in the tumor was clearly visualized, and the maximum standardized uptake value (SUV) was significantly decreased after treatment with cetuximab (p<0.01). Ki-67 expression was also significantly decreased on day 3 (p=0.01). These results suggest that F-18-FLT-PET/CT can be a useful predictor to determine the response to molecular targeted drugs such as cetuxima.b at an earlier time point than the change of tumor size.
• Localization of Deoxyglucose and Annexin A5 in Experimental Atheroma Correlates with Macrophage Infiltration but not Lipid Deposition in the Lesion

  Yan Zhao, Songji Zhao, Yuji Kuge, William H. Strauss, Francis G. Blankenberg, Nagara Tamaki

  MOLECULAR IMAGING AND BIOLOGY 13 (4) 712 - 720 1536-1632 2011/08 [Refereed][Not invited]
   

  The aim of this study was to understand the relationship of lipid deposition to the macrophage content, macrophage metabolism, and apoptosis in plaque. We compared the uptake of 2-deoxy-2-fluoro-D-[C-14]glucose ([C-14]FDG) and [Tc-99m]HYNIC-annexin V ([Tc-99m]annexin A5) with the lesion histology in apolipoprotein E knockout (apoE(-/-)) mice. Male apoE(-/-) mice (n = 9) were injected with [C-14]FDG and [Tc-99m]annexin A5. Cryostat sections of aorta samples (n = 49) were used for dual-tracer autoradiography, and regional tracer uptake levels were evaluated. Lesions were identified histologically with Movat's pentachrome (AHA lesion phenotypes), Mac-2 staining (macrophage infiltration) and Oil Red O staining (lipid deposition). The highest uptakes of [C-14]FDG (3.10 +/- 1.50 %ID x kilogram per square millimeter) and [Tc-99m]annexin A5 (0.49 +/- 0.20 %ID x kilogram per square millimeter) were shown in atheromatous lesions (types III and IV). Each tracer uptake showed better correlation with macrophage infiltration than lipid deposition ([C-14]FDG, r = 0.44 vs. r = 0.14; [Tc-99m]annexin A5, r = 0.65 vs. r = 0.48). Both tracers were concentrated in type III and IV atheromatous lesions which corresponded to macrophage infiltration rather than lipid deposition.
• Gene and protein analysis of brain derived neurotrophic factor expression in relation to neurological recovery induced by an enriched environment in a rat stroke model

  Kenji Hirata, Yuji Kuge, Chiaki Yokota, Akina Harada, Koichi Kokame, Hiroyasu Inoue, Hidekazu Kawashima, Hiroko Hanzawa, Yuji Shono, Hideo Saji, Kazuo Minematsu, Nagara Tamaki

  NEUROSCIENCE LETTERS 495 (3) 210 - 215 0304-3940 2011/05 [Refereed][Not invited]
   

  Although an enriched environment enhances functional recovery after ischemic stroke, the mechanism underlying this effect remains unclear. We previously reported that brain derived neurotrophic factor (BDNF) gene expression decreased in rats housed in an enriched environment for 4 weeks compared to those housed in a standard cage for the same period. To further clarify the relationship between the decrease in BDNF and functional recovery, we investigated the effects of differential 2-week housing conditions on the mRNA of BDNF and protein levels of proBDNF and mature BDNF (matBDNF). After transient occlusion of the right middle cerebral artery of male Sprague-Dawley rats, we divided the rats into two groups: (1) an enriched group housed multiply in large cages equipped with toys, and (2) a standard group housed alone in small cages without toys. Behavioral tests before and after 2-week differential housing showed better neurological recovery in the enriched group than in the standard group. Synaptophysin immunostaining demonstrated that the density of synapses in the pen-infarct area was increased in the enriched group compared to the standard group, while infarct volumes were not significantly different. Real-time reverse transcription polymerase chain reaction. Western blotting and immunostaining all revealed no significant difference between the groups. The present results suggest that functional recovery cannot be ascribed to an increase in matBDNF or a decrease in proBDNF but rather to other underlying mechanisms. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
• Performance characterization of the Inveon preclinical small-animal PET/SPECT/CT system for multimodality imaging

  Keiichi Magota, Naoki Kubo, Yuji Kuge, Ken-ichi Nishijima, Songji Zhao, Nagara Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 38 (4) 742 - 752 1619-7070 2011/04 [Refereed][Not invited]
   

  We investigated the performance of the Inveon small-animal PET/SPECT/CT system and compared the imaging capabilities of the SPECT and PET components. For SPECT, the energy resolution, tomographic spatial resolution and system sensitivity were evaluated with a (99m)Tc solution using a single pinhole collimator. For PET, the spatial resolution, absolute sensitivity, scatter fraction and peak noise equivalent count were evaluated. Phantoms and a normal rat were scanned to compare the imaging capabilities of SPECT and PET. The SPECT spatial resolution was 0.84 mm full-width at half-maximum (FWHM) at a radius of rotation of 25 mm using a 0.5-mm pinhole aperture collimator, while the PET spatial resolution was 1.63 mm FWHM at the centre. The SPECT system sensitivity at a radius of rotation of 25 mm was 35.3 cps/MBq (4 x 10(-3)%) using the 0.5-mm pinhole aperture, while the PET absolute sensitivity was 3.2% for 350-650 keV and 3.432 ns. Accordingly, the volume sensitivity of PET was three orders of magnitude higher than that of SPECT. This integrated PET/SPECT/CT system showed high performance with excellent spatial resolution for SPECT and sensitivity for PET. Based on the tracer availability and system performance, SPECT and PET have complementary roles in multimodality small-animal imaging.
• Semiquantitative analysis of C-11 methionine PET may distinguish brain tumor recurrence from radiation necrosis even in small lesions

  Shozo Okamoto, Tohru Shiga, Naoya Hattori, Naoki Kubo, Toshiki Takei, Norio Katoh, Yutaka Sawamura, Kenichi Nishijima, Yuji Kuge, Nagara Tamaki

  ANNALS OF NUCLEAR MEDICINE 25 (3) 213 - 220 0914-7187 2011/04 [Refereed][Not invited]
   

  (11)C-Methionine positron emission tomography (MET-PET) has been used to distinguish brain tumor recurrence from radiation necrosis. Because the spatial resolution of conventional PET scanners is low, partial volume effect (PVE) may decrease the detectability of small tumor recurrence. The aim of this study is to investigate the diagnostic value of MET-PET upon semiquantitative analyses in particular PVE-affected small lesions. First, we performed a phantom experiment to investigate what size lesion is affected by PVE. This study included 29 patients (33 lesions) suspected of recurrent brain tumors by magnetic resonance imaging (MRI) after radiation therapy. All of them received MET-PET. Semiquantitative analysis was performed using maximum standardized uptake value (SUVmax) and lesion-versus-normal ratio (L/N ratio). ROC analysis was also assessed about the diagnostic value of MET-PET. From the result of the phantom experiment, lesions smaller than 20 mm in brain mode or smaller than 30 mm in whole-body mode were defined as PVE-affected lesions. Histological analysis or clinical follow-up confirmed the diagnosis of tumor recurrence in 22 lesions, and radiation necrosis in 11 lesions. L/N ratios of recurrence and necrosis for overall lesions were 1.98 +/- A 0.62 and 1.27 +/- A 0.28, respectively (p < 0.01). In the PVE-affected lesions, L/N ratio for recurrence (1.72 +/- A 0.44) was also significantly higher than that for necrosis (1.20 +/- A 0.11) (p < 0.01). On the ROC analysis for the PVE-affected lesions, the area under the curve for L/N ratio (0.897) was significantly higher than that for SUVmax (0.718) (p < 0.05). These areas under the curve were almost equal to that of overall lesions for L/N ratio (0.886) and for SUVmax (0.738). Semiquantitative analysis of MET provided high diagnostic value even for PVE-affected small lesions. MET-PET enables early diagnosis of recurrence of brain tumor in the follow-up after the radiation therapy.
• Near-Infrared Fluorescence Labeling Allows Noninvasive Tracking of Bone Marrow Stromal Cells Transplanted Into Rat Infarct Brain

  Taku Sugiyama, Satoshi Kuroda, Toshiya Osanai, Hideo Shichinohe, Yuji Kuge, Masaki Ito, Masahito Kawabori, Yoshinobu Iwasaki

  NEUROSURGERY 68 (4) 1036 - 1047 0148-396X 2011/04 [Refereed][Not invited]
   

  BACKGROUND: Noninvasive imaging techniques would be needed to validate the therapeutic benefits of cell transplantation therapy for central nervous system disorders. OBJECTIVE: To evaluate whether near-infrared (NIR)-emitting fluorescence tracer, quantum dots, would be useful to noninvasively visualize the bone marrow stromal cells (BMSC) transplanted into the infarct brain in living animals. METHODS: Rat BMSCs were labeled with QD800. In vitro and in vivo conditions to visualize NIR fluorescence were precisely optimized. The QD800-labeled BMSCs were stereotactically transplanted into the ipsilateral striatum of the rats subjected to permanent middle cerebral artery occlusion 7 days after the insult. Using the NIR fluorescence imaging technique, the behaviors of BMSCs were serially visualized during the 8 weeks after transplantation. RESULTS: NIR fluorescence imaging could noninvasively detect the NIR fluorescence emitted from the transplanted BMSCs engrafted in the peri-infarct neocortex through the scalp up to 8 weeks after transplantation. The intensity gradually increased and reached the peak at 4 weeks. The results were supported by the findings on ex vivo NIR fluorescence imaging and histological analysis. CONCLUSION: NIR fluorescence imaging is valuable in monitoring the behaviors of donor cells in the rodent brain. The results would allow new opportunities to develop noninvasive NIR fluorescence imaging as a modality to track the BMSCs transplanted into the brain.
• Gene expression associated with an enriched environment after transient focal ischemia

  Yuji Shono, Chiaki Yokota, Yuji Kuge, Shinsuke Kido, Akina Harada, Koichi Kokame, Hiroyasu Inoue, Mariko Hotta, Kenji Hirata, Hideo Saji, Nagara Tamaki, Kazuo Minematsu

  BRAIN RESEARCH 1376 60 - 65 0006-8993 2011/02 [Refereed][Not invited]
   

  Recent studies have demonstrated that animals housed in an enriched environment after an experimental stroke obtained a better functional outcome than those housed in a standard cage; however, little is known about the gene expression associated with this functional recovery. The purpose of the present study was to elucidate the expression of genes in an enriched environment after experimental stroke in the ischemic and non-ischemic sides of the cortices. Transient focal brain ischemia was produced by the occlusion of the right middle cerebral artery (t-MCAO) in male Sprague Dawley rats. The rats were divided into 3 groups: ischemic rats housed in the enriched environment, ischemic rats housed in standard cages, and non-ischemic rats in standard cages. Four weeks after t-MCAO, the rats were sacrificed and gene expression was examined. Motor function was improved in ischemic rats housed in the enriched environment compared with those in standard cages; however, there were no significant differences in the size of the infarct area between the ischemic rats in the enriched environment and those in standard cages. Decreases in the expression of Egr-1, -2, and BDNF mRNA in both sides of the cortices were detected in rats housed in the enriched environment, indicating that gene expression was altered throughout the brain at 4 weeks after transient focal ischemia. (C) 2010 Elsevier B.V. All rights reserved.
• Regional partition coefficient of water in patients with cerebrovascular disease and its effect on rCBF assessment

  Kenji Hirata, Naoya Hattori, Chietsugu Katoh, Tohru Shiga, Satoshi Kuroda, Naoki Kubo, Reiko Usui, Yuji Kuge, Nagara Tamaki

  NUCLEAR MEDICINE COMMUNICATIONS 32 (1) 63 - 70 0143-3636 2011/01 [Refereed][Not invited]
   

  Objective Cerebral blood flow (CBF) estimation with C(15)O(2) PET usually assumes a single tissue compartment model and a fixed brain-blood partition coefficient of water. However, the partition coefficient may change in pathological conditions. The purpose of this study was to investigate the changes in the partition coefficient of water in pathological regions and its effect on regional CBF assessment. Methods The study protocol included 22 patients with occlusive cerebrovascular disease to compare the partition coefficients among three regions (infarction area, noninfarct hypoperfusion area, and contralateral area) in the pathological brain (analysis A), and to compare the CBF estimated by using a fixed partition coefficient and CBF estimated using floating partition coefficients (analysis B). Results The partition coefficient in the infarction area (0.55 +/- 0.07 ml/g) was lower than that in the contralateral normal cortex (0.68 +/- 0.05 ml/g), whereas noninfarct hypoperfusion area did not show a significant change (0.67 +/- 0.06 ml/g). As a result, the use of a fixed partition coefficient of normal volunteers (0.70 ml/g) resulted in an underestimation in regional CBF by 12% in infarction area (P<0.05), whereas the estimation errors were smaller and induced no significant difference in the noninfarct hypoperfusion area or in contralateral areas. Conclusion The partition coefficient is stable except for the infarction area, and CBF estimation using a fixed partition coefficient of normal volunteers provides clinically appreciable information in patients with cerebrovascular disease. Nucl Med Commun 32:63-70 (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.
• Tissue Factor Detection for Selectively Discriminating Unstable Plaques in an Atherosclerotic Rabbit Model

  Takashi Temma, Yuki Ogawa, Yuji Kuge, Seigo Ishino, Nozomi Takai, Kantaro Nishigori, Masashi Shiomi, Masahiro Ono, Hideo Saji

  JOURNAL OF NUCLEAR MEDICINE 51 (12) 1979 - 1986 0161-5505 2010/12 [Refereed][Not invited]
   

  Tissue factor (TF), a transmembrane glycoprotein that acts as an essential cofactor to factor VII/VIIa, initiates the exogenous blood coagulation cascade leading to thrombin generation and subsequent thrombus formation in vivo. TF expression is closely related to plaque vulnerability, and high TF expression is shown in macrophage-rich atheromatous lesions, making TF a potential target for detecting atheromatous lesions in vivo. Thus, we prepared (99m)Tc-labeled anti-TF-monoclonal antibody (TF-mAb) IgG as a molecular probe and evaluated its usefulness to achieve TF-specific imaging using myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHLMI) rabbits. Methods: Anti-TF-mAb was created using a standard hybridoma technique and was labeled by (99m)Tc with 6-hydrazinonicotinic acid (HYNIC) as a chelating agent to obtain (99m)Tc-TF-mAb. The immunoreactivity of HYNIC-TF-mAb was estimated by flow cytometry. WHHLMI and control rabbits were injected intravenously with (99m)Tc-TF-mAb. Twenty-four hours after the injection, the aorta was removed and radioactivity was measured. Autoradiography and histologic studies were performed using serial aorta sections. Subclass matched antibody (IgG(1)) was used as a negative control. Results: HYNIC-TF-mAb showed 93% immunoreactivity of the anti-TF-mAb. The radioactivity accumulation in WHHLMI aortas was 6.1-fold higher than that of control rabbits. Auto-radiograms showed a heterogeneous distribution of radioactivity in the intima of WHHLMI aortas. Regional radioactivity accumulation was positively correlated with TF expression density (R = 0.64, P < 0.0001). The highest radioactivity accumulation in percentage injected dose x body weight/mm(2) x 10(2) was found in atheromatous lesions (5.2 +/- 1.9) followed by fibroatheromatous (2.1 +/- 0.7), collagen-rich (1.8 +/- 0.7), and neointimal lesions (1.8 +/- 0.6). In contrast, (99m)Tc-IgG(1) showed low radioactivity accumulation in WHHLMI aortas that was independent of the histologic grade of lesions. Conclusion: The TF-detecting ability and preferential accumulation in atheromatous lesions of (99m)Tc-TF-mAb were demonstrated, indicating its potential for selective imaging of macrophage-rich atheromatous lesions in vivo.
• Imaging with radiolabelled anti-membrane type 1 matrix metalloproteinase (MT1-MMP) antibody: potentials for characterizing atherosclerotic plaques

  Yuji Kuge, Nozomi Takai, Yuki Ogawa, Takashi Temma, Yan Zhao, Kantaro Nishigori, Seigo Ishino, Junko Kamihashi, Yasushi Kiyono, Masashi Shiomi, Hideo Saji

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 37 (11) 2093 - 2104 1619-7070 2010/11 [Refereed][Not invited]
   

  Purpose Membrane type 1 matrix metalloproteinase (MT1-MMP) activates pro-MMP-2 and pro-MMP-13 to their active forms and plays important roles in the destabilization of atherosclerotic plaques. This study sought to determine the usefulness of (99m)Tc-labelled monoclonal antibody (mAb), recognizing MT1-MMP, for imaging atherosclerosis in a rabbit model (WHHLMI rabbits). Methods Anti-MT1-MMP monoclonal IgG(3) and negative control IgG(3) were radiolabelled with (99m)Tc after derivatization with 6-hydrazinonicotinic acid (HYNIC) to yield (99m)Tc-MT1-MMP mAb and (99m)Tc-IgG(3), respectively. WHHLMI and control rabbits were injected with these radio-probes. The aorta was removed and radioactivity was measured at 24 h after the injection. Autoradiography and histological studies were performed. Results (99m)Tc-MT1-MMP mAb accumulation in WHHLMI rabbit aortas was 5.4-fold higher than that of control rabbits. Regional (99m)Tc-MT1-MMP mAb accumulation was positively correlated with MT1-MMP expression (r = 0.59, p < 0.0001), while (99m)Tc-IgG(3) accumulation was independent of MT1-MMP expression (r = 0.03, p = NS). The highest (99m)Tc-MT1-MMP mAb accumulation was found in atheromatous lesions (4.8 +/- 1.9, %IDxBW/mm(2) x 10(2)), followed in decreasing order by fibroatheromatous (1.8 +/- 1.3), collagen-rich (1.6 +/- 1.0) and neointimal lesions (1.5 +/- 1.5). In contrast, (99m)Tc-IgG(3) accumulation was almost independent of the histological grade of lesions. Conclusion Higher (99m)Tc-MT1-MMP mAb accumulation in grade IV atheroma was shown in comparison with neointimal lesions or other more stable lesions. Nuclear imaging with (99m)Tc-MT1-MMP mAb, in combination with CT and MRI, could provide new diagnostic imaging capabilities for detecting vulnerable plaques, although further investigations to improve target to blood ratios are strongly required.
• Radioimmunodetection of Membrane Type-1 Matrix Metalloproteinase Relevant to Tumor Malignancy with a Pre-targeting Method

  Kohei Sano, Takashi Temma, Yuji Kuge, Takashi Kudo, Junko Kamihashi, Songji Zhao, Hideo Saji

  BIOLOGICAL & PHARMACEUTICAL BULLETIN 33 (9) 1589 - 1595 0918-6158 2010/09 [Refereed][Not invited]
   

  Since membrane type-1 matrix metalloproteinase (MT1-MMP) is exclusively expressed in tumors and is closely associated with metastasis and invasion, MT1-MMP is a potential target of radiotracers for the evaluation of tumor malignancy. In this study, we planned to visualize MT1-MMP in vivo by a two-step pre-targeting strategy using a streptavidin (SAv)-biotin system combined with anti-MT1-MMP monoclonal immunoglobulin (IgG) (anti-MT1-MMP monoclonal antibody (mAb)). Streptavidinylated anti-MT1-MMP mAb was synthesized by reacting biotinylated anti-MT1-MMP mAb with SAv. In the pre-targeting study, FM3A mouse breast carcinoma-implanted mice were injected with anti-MT1-MMP mAb-SAv, followed 72 h later with radioiodinated biotin, (3-[I-123/125]iodobenzoyl)norbiotinamide (I-123/125-IBB). Biodistribution and imaging (single photon emission computed tomography (SPECT)/CT) data were collected at several time points in the 24 h period following introduction of the tracer. The comparison groups were injected with I-125-IBB alone or with I-125-IBB pre-targeted with negative control IgG-SAv. In the pre-targeting study for MT1-MMP, within 1 h of tracer injection, rapid tumor uptake and abrupt clearance from the blood of radioactivity (2.22, 0.87% injected dose/g at 1 h) were observed. The tumor to blood (T/B) radioactivity ratios were significantly higher than those from mice dosed with the pre-targeting negative control (p<0.0001). I-125-IBB alone did not accumulate in tumors. SPECT/CT image analysis of FM3A bearing mice showed high-contrast tumor images after 3 h with minimal blood-pool activity. The present study that uses a pre-targeting method showed high T/B radioactivity ratios and clear tumor images of MT1-MMP. This imaging method may be useful for the clinical diagnosis of malignant tumors.
• Rapid detection of hypoxia-inducible factor-1-active tumours: pretargeted imaging with a protein degrading in a mechanism similar to hypoxia-inducible factor-1 alpha

  Masashi Ueda, Takashi Kudo, Yuji Kuge, Takahiro Mukai, Shotaro Tanaka, Hiroaki Konishi, Azusa Miyano, Masahiro Ono, Shinae Kizaka-Kondoh, Masahiro Hiraoka, Hideo Saji

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 37 (8) 1566 - 1574 1619-7070 2010/08 [Refereed][Not invited]
   

  Hypoxia-inducible factor-1 (HIF-1) plays an important role in malignant tumour progression. For the imaging of HIF-1-active tumours, we previously developed a protein, POS, which is effectively delivered to and selectively stabilized in HIF-1-active cells, and a radioiodinated biotin derivative, (3-(123)I-iodobenzoyl)norbiotinamide ((123)I-IBB), which can bind to the streptavidin moiety of POS. In this study, we aimed to investigate the feasibility of the pretargeting method using POS and (123)I-IBB for rapid imaging of HIF-1-active tumours. Tumour-implanted mice were pretargeted with POS. After 24 h, (125)I-IBB was administered and subsequently, the biodistribution of radioactivity was investigated at several time points. In vivo planar imaging, comparison between (125)I-IBB accumulation and HIF-1 transcriptional activity, and autoradiography were performed at 6 h after the administration of (125)I-IBB. The same sections that were used in autoradiographic analysis were subjected to HIF-1 alpha immunohistochemistry. (125)I-IBB accumulation was observed in tumours of mice pretargeted with POS (1.6%ID/g at 6 h). This result is comparable to the data derived from (125)I-IBB-conjugated POS-treated mice (1.4%ID/g at 24 h). In vivo planar imaging provided clear tumour images. The tumoral accumulation of (125)I-IBB significantly correlated with HIF-1-dependent luciferase bioluminescence (R=0.84, p < 0.01). The intratumoral distribution of (125)I-IBB was heterogeneous and was significantly correlated with HIF-1 alpha-positive regions (R=0.58, p < 0.0001). POS pretargeting with (123)I-IBB is a useful technique in the rapid imaging and detection of HIF-1-active regions in tumours.
• In vitro and in vivo evaluations of a radioiodinated thymidine phosphorylase inhibitor as a tumor diagnostic agent for angiogenic enzyme imaging

  Hiromichi Akizawa, Songji Zhao, Masayuki Takahashi, Ken-ichi Nishijima, Yuji Kuge, Nagara Tamaki, Koh-ichi Seki, Kazue Ohkura

  NUCLEAR MEDICINE AND BIOLOGY 37 (4) 427 - 432 0969-8051 2010/05 [Refereed][Not invited]
   

  Introduction: The expression of thymidine phosphorylase (TP) is closely associated with angiogenesis, tumor invasiveness and activation of. antitumor agents. We evaluated radioiodinated 5-iodo-6-[(2-iminoimidazolidinyl)methyl]uracil ([(125)I]IIMU) having high TP-inhibitory potency as the new radiotracer for SPECT targeting of TP expression in tumors. Methods: The characteristics of the radioiodinated TP inhibitor IIMU were determined by evaluating the uptake by tumor cells in vitro and by biodistribution studies in vivo. The distribution of the radiotracer and the extent of TP-specific uptake by tumors were evaluated by a counting method in tumor-bearing mice. Results: The in vitro uptake of radiolabeled IIMU by A431 cells along with high TP expressions was attributed to the binding of the radiotracer to its target enzyme, i.e., TP. In vivo distribution of the radiotracer in A431 tumor-bearing mice revealed tumor/blood and tumor/muscle activity uptake ratios of 36 and 106, respectively, at 3 h after the radiotracer injection. On using low TP-expressing tumors and TP blocking studies as controls, minor TP-specific accumulation of the radiotracer was detected in these studies. Conclusion: According to the binding of radioiodinated IIMU to the angiogenic enzyme TP, it can be concluded that radioiodinated IIMU might be suitable as a SPECT tracer for tumor imaging. (C) 2010 Elsevier Inc. All rights reserved.
• Isolation and identification of new vasodilative substances in diesel exhaust particles

  Koh-ichi Seki, Yoichi Noya, Yusuke Mikami, Shinji Taneda, Akira K. Suzuki, Yuji Kuge, Kazue Ohkura

  ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH 17 (3) 717 - 723 0944-1344 2010/03 [Refereed][Not invited]
   

  We recently developed a new isolation method for diesel exhaust particles (DEP), involving successive extraction with H(2)O, sodium bicarbonate, and sodium hydroxide, in which the sodium hydroxide extract was found to consist of phenolic components. Analysis of the extract revealed that vasodilative-active nitrophenols are in DEP in significantly higher concentrations than those estimated by an earlier method involving a combination of solvent extraction and repeated chromatography. These findings indicated that our new procedure offers a simple, efficient, and reliable method for the isolation and identification of bioactive substances in DEP. This encouraged us to extend our work toward investigating new vasodilatory substances in the sodium bicarbonate extract. DEP were collected from the exhaust of a 4JB1-type engine (ISUZU Automobile Co., Tokyo, Japan). GC-MS analysis was performed with a GCMS-QP2010 instrument (Shimadzu, Kyoto, Japan). DEP dissolved in 1-butanol was successively extracted with water, sodium bicarbonate, and then aqueous sodium hydroxide. The sodium bicarbonate extract was neutralized and the resulting mixture of acidic components was subjected to reverse-phase (RP) column chromatography followed by RP-HPLC with fractions assayed for vasodilative activity. This led to the identification of terephthalic acid, p-hydroxybenzoic acid, isophthalic acid, phthalic acid, 3-hydroxy-4-nitrobenzoic acid, 4-hydroxy-3-nitrophenol, and 1,4,5-naphthalene tricarboxylic acid as components of DEP. The sodium bicarbonate extract was rich in aromatic carboxylic acid components. Repeated reverse-phase chromatography resulted in the successful isolation of several acidic substances including the new vasodilative materials, 4-hydroxy-3-nitrobenzoic acid, and 3-hydroxy-4-nitrobenzoic acid. Our new fractionation method for DEP has made possible the isolation of new vasodilative compounds from the sodium bicarbonate extract.
• Nicotinic acetylcholine receptors expressed in the ventralposterolateral thalamic nucleus play an important role in anti-allodynic effects

  M. Ueda, Y. Iida, A. Tominaga, T. Yoneyama, M. Ogawa, Y. Magata, H. Nishimura, Y. Kuge, H. Saji

  BRITISH JOURNAL OF PHARMACOLOGY 159 (6) 1201 - 1210 0007-1188 2010/03 [Refereed][Not invited]
   

  Background and purpose: Much interest is currently being focused on the anti-nociceptive effects mediated by nicotinic acetylcholine (nACh) receptors, including their location and mechanism of action. The purpose of this study was to elucidate these issues using 5-iodo-3-(2(S)-azetidinylmethoxy)pyridine (5IA), a nACh receptor agonist, and [125I]5IA. Experimental approach: We partially ligated the sciatic nerve of Sprague-Dawley rat to induce neuropathic pain [Seltzer's partial sciatic nerve ligation (PSL) model]. We then examined the changes in nACh receptor density in the CNS using [125I]5IA autoradiography and the involvement of nACh receptors in anti-nociceptive effects in the region where changes occurred. Key results: Autoradiographic studies showed that the accumulation of [125I]5IA and the number of nACh receptors in the thalamus of PSL rats were increased about twofold compared with those in the sham-operated rats. No change was observed in other brain regions. Rats injected in the ventral posterolateral thalamic nucleus (VPL) with 5IA demonstrated a significant and dose-dependent anti-allodynic effect and this effect was completely antagonized by mecamylamine, injected with 5IA, into the VPL. The blockade of nACh receptors in the VPL by mecamylamine decreased by 70% the anti-allodynic effect of 5IA, given i.c.v. Moreover, mecamylamine given intra-VPL by itself, induced significant hyperalgesia. Conclusions and implications: Our findings suggest that the nACh receptors expressed in the VPL play an important role in the anti-allodynic effects produced by exogenous and endogenous agonists.
• Synthesis of a New NIR Fluorescent Nd Complex Labeling Agent

  Kazuki Aita, Takashi Temma, Yoichi Shimizu, Yuji Kuge, Koh-ichi Seki, Hideo Saji

  JOURNAL OF FLUORESCENCE 20 (1) 225 - 234 1053-0509 2010/01 [Refereed][Not invited]
   

  Fluorescent analysis has been widely used in biological, chemical and analytical research. A useful fluorescent labeling agent should include NIR emission, a large Stoke's shift, and good labeling ability without interfering with the pharmacological profile of the labeled compound. Thus, we planned to develop an M-AMF-DOTA(Nd) derivative composed of an NIR fluorescent moiety and a maleimide conjugating moiety as a new NIR fluorescent labeling agent which fulfills these requirements. M-AMF-DOTA(Nd) was synthesized from 4-amino-fluorescein and was conjugated with an avidin molecule (Avidin-AMF-DOTA(Nd)) through Lys-side chains by reaction with 2-iminothiolane. The fluorescent features of M-AMF-DOTA(Nd) and Avidin-AMF-DOTA(Nd) were comparatively evaluated. A binding assay of Avidin-AMF-DOTA(Nd) with D-biotin and a tumor cell-uptake study were performed to estimate the effects of conjugation on the biological and physicochemical features of the protein. M-AMF-DOTA(Nd) was obtained in 22% overall yield. M-AMF-DOTA(Nd) had a typical NIR fluorescence from the Nd ion (880 nm and 900 nm from 488 nm excitation). Avidin-AMF-DOTA(Nd) was easily synthesized and also had typical NIR fluorescence from the Nd ion without loss of fluorescent intensity. The binding affinity of Avidin-AMF-DOTA(Nd) to D-biotin was equivalent to naive avidin. Avidin-AMF-DOTA(Nd) was taken up by tumor cells in the same manner as avidin conjugated with fluorescein isothiocyanate, an established, widely used fluorescent avidin. Results from this study indicate that M-AMF-DOTA(Nd) is a potential labeling agent for routine NIR fluorescent analysis.
• NIR fluorescent ytterbium compound for in vivo fluorescence molecular imaging

  Kazuki Aita, Takashi Temma, Yuji Kuge, Koh-ichi Seki, Hideo Saji

  LUMINESCENCE 25 (1) 19 - 24 1522-7235 2010/01 [Refereed][Not invited]
   

  We have developed a new NIR fluorescent probe based on an ytterbium(III) (E)-1-(pyridin-2-yl-diazenyl)naphthalen-2-ol (PAN) complex. This probe emits near-infrared luminescence derived from the Yb ion through excitation of the PAN moiety with visible light (lambda(ex) = 530 lambda(em) = 975 nm). The results support the possible utility of the probe for in vivo fluorescence molecular imaging. Copyright (C) 2009 John Wiley & Sons, Ltd.
• Synthesis and evaluation of a radioiodinated lumiracoxib derivative for the imaging of cyclooxygenase-2 expression

  Yuji Kuge, Naoyuki Obokata, Hiroyuki Kimura, Yumiko Katada, Takashi Temma, Yukihiko Sugimoto, Kazuki Aita, Koh-ichi Seki, Nagara Tamaki, Hideo Saji

  NUCLEAR MEDICINE AND BIOLOGY 36 (8) 869 - 876 0969-8051 2009/11 [Refereed][Not invited]
   

  Introduction: Despite extensive attempts to develop cyclooxygenase (COX)-2 imaging radiotracers, no suitable positron emission tomography (PET)/single photon emission computed tomography (SPECT) tracers are currently available for in vivo imaging of COX-2 expression. The aims of this study were to synthesize and evaluate a radioiodinated derivative of lumiracoxib, 2-[(2-fluoro-6-iodophenyl)-amino]-5-methylphenylacetic acid (FIMA), which is structurally distinct from other drugs in the class and has weakly acidic properties, as a SPECT tracer for imaging COX-2 expression. Methods: The COX inhibitory potency was assessed by measuring COX-catalyzed oxidation with hydrogen peroxide. Cell uptake characteristics of (125)I-FIMA were assessed in control and linterfero/interferon-gamma-stimulated macrophages. The biodistribution of (125)I-FIMA was determined by the ex vivo tissue counting method in rats. Results: The COX-2 inhibitory potency of FIMA (IC(50)=2.46 mu M) was higher than that of indomethacin (IC(50)=20.9 mu M) and was comparable to lumiracoxib (IC(50)=0.77 mu M) and diclofenac (IC(50)=0.98 mu M). The IC(50) ratio (COX-1/COX-2=182) indicated FIMA has a high isoform selectivity for COX-2. (125)I-FIMA showed a significantly higher accumulation in COX-2 induced macrophages than in control macrophages, which decreased with nonradioactive FIMA in a concentration dependent manner. The biodistribution Study showed rapid clearance of (125)I-FIMA from the blood and most organs including the liver and kidneys. No significant in vivo deiodination was observed with radioiodinated FIMA. Conclusions: FIMA showed high inhibitory potency and selectivity for COX-2. Radioiodinated FIMA showed specific accumulation into COX-2 induced macrophages, no significant in vivo deiodination and rapid blood clearance. Radioiodinated FIMA deserves further investigation as a SPECT radiopharmaceutical for imaging COX-2 expression. (C) 2009 Elsevier Inc. All rights reserved.
• Clinical Value and Limitations of [C-11]-Methionine PET for Detection and Localization of Suspected Parathyroid Adenomas

  Ken Herrmann, Toshiki Takei, Kakuko Kanegae, Tohru Shiga, Andreas K. Buck, Jennifer Altomonte, Markus Schwaiger, Tibor Schuster, Kenichi Nishijima, Yuji Kuge, Nagara Tamaki

  MOLECULAR IMAGING AND BIOLOGY 11 (5) 356 - 363 1536-1632 2009/09 [Refereed][Not invited]
   

  The aim of this study was to assess the clinical value of [C-11]methionine-PET (MET-PET) for detection and localization of parathyroid adenomas in patients without prior thyroidectomy. A retrospective analysis of patients with suspected parathyroid adenomas undergoing imaging with MET-PET was performed. Prior thyroidectomy was an exclusion criterion. Forty-one patients with a total of 49 MET-PET scans were included. MET-PET consisted of whole-body images obtained 15-20 min after injection of 430 +/- 81 MBq of MET using a dedicated PET scanner. Imaging findings were validated by histology or other imaging studies and clinical follow-up on a lesion, side, and location basis. Comparison of PET results to other imaging modalities including ultrasound, MIBI scintigraphy, and morphological imaging [computed tomography (CT) and/or magnetic resonance imaging] and subgroup analysis of primary vs. secondary hyperparathyroidism was performed. Twenty-three of 49 PET scans revealed pathologic findings, whereas 26 of 49 scans were negative. Validation of PET findings for detection and localization of parathyroid adenomas resulted in an overall sensitivity of MET-PET of 54%, 49%, and 35% on a lesion, side, and location basis, respectively. Sensitivity of MET-PET was inferior compared to ultrasonography (50% vs. 93%), MIBI scintigraphy (53% vs. 74%) and morphological imaging (52% vs. 74%). Subgroup analysis revealed higher sensitivity for MET-PET in secondary HPT (sHPT) than primary HPT (pHPT; 62% vs. 43%; side basis). In patients with initial diagnosis of hyperparathyroidism and no prior thyroidectomy, the sensitivity of MET-PET for detection and localization of parathyroid adenomas is markedly lower compared to previous reports. While performance was better in sHPT, we believe that MET-PET cannot be recommended for pHPT localization in this clinically relevant subcollective. The clinical value of MET/PET in patients with hyperparathyroidism should be further investigated in a prospective study utilizing anatometabolic imaging with a PET/CT device.
• Development of a Radiolabeled Probe for Detecting Membrane Type-1 Matrix Metalloproteinase on Malignant Tumors

  Takashi Temma, Kohei Sano, Yuji Kuge, Junko Kamihashi, Nozomi Takai, Yuki Ogawa, Hideo Saji

  BIOLOGICAL & PHARMACEUTICAL BULLETIN 32 (7) 1272 - 1277 0918-6158 2009/07 [Refereed][Not invited]
   

  Membrane type-1 matrix metalloproteinase (MT1-MMP) expressed on the tumor cell surface activates pro-MMP-2 and pro-MMP-13 to exacerbate the malignancy, suggesting its suitability as a target molecule for diagnosis by in vivo molecular imaging. Thus, we prepared radiolabeled anti-MT1-MMP monoclonal antibody (mAb) as a novel radiolabeled probe for detecting MT1-MMP in vivo and evaluated its usefulness in breast tumor-bearing rodents. Tc-99m-anti-MT1-MMP mAb was prepared using HYNIC as a bifunctional chelating agent and immunoreactivity was evaluated by flow cytometry. MT1-MMP expression in breast carcinoma cells (rat: Walker-256 and MRMT-1, mouse: FM3A) was measured by Western blotting. In vivo biodistribution was examined for 48 h using tumor-implanted rodents followed by estimation of radiation absorbed by a standard quantitation platform Organ Level Internal Dose Assessment (OLINDA). Tc-99m-anti-MT1-MMP mAb was obtained with 84% immunoreactivity to MT1-MMP and more than 92% radiochemical purity. MT1-MMP was highly expressed in all malignant cells. Tumor radioactivity increased with time after administration and reached 3 to 5 times higher values at 24 h post-injection than those at I h. Other organs, including the stomach, showed decreasing values over time. Tumor to blood ratios increased with time and reached more than 1.3 at 48 h. The effective dose was <5.0 mu Sv/MBq. The results suggest that Tc-99m-anti-MT1-MMP mAb is a promising probe for future diagnosis of breast tumors by in vivo nuclear medical imaging.
• Imaging of HIF-1-Active Tumor Hypoxia Using a Protein Effectively Delivered to and Specifically Stabilized in HIF-1-Active Tumor Cells

  Takashi Kudo, Masashi Ueda, Yuji Kuge, Takahiro Mukai, Shotaro Tanaka, Maki Masutani, Yasushi Kiyono, Shinae Kizaka-Kondoh, Masahiro Hiraoka, Hideo Saji

  JOURNAL OF NUCLEAR MEDICINE 50 (6) 942 - 949 0161-5505 2009/06 [Refereed][Not invited]
   

  Hypoxia-inducible factor-1 (HIF-1) plays an important role in malignant tumor progression and in the development of resistance to radiotherapy. We designed a novel fusion protein (PTD-ODD-SAV [POS]) consisting of a protein transduction domain (PTD), streptavidin (SAV), and a portion of the oxygen-dependent degradation domain (ODD) of HIF-1 alpha that confers the same oxygen-dependent regulation as HIF-1 alpha on POS. (3-(123/125)I-iodobenzoyl) norbiotinamide ((123/125)I-IBB) was conjugated to the SAV moiety of POS to synthesize (123/125)I-IBB-labeled POS ((123/125)I-IPOS). The purpose of this study was to evaluate the feasibility of (123)I-IPOS as an imaging probe for HIF-1-active tumor hypoxia. Methods: After a 24-h incubation of (125)I-IPOS with various tumor cell lines under either normoxic (20% O(2)) or hypoxic (0.1% O(2)) conditions, the intracellular radioactivity was investigated. Then, the biodistribution of (123/125)I-IPOS was examined with tumor-implanted mice, and an in vivo imaging study was performed. The tumoral accumulation of (125)I-IPOS was compared with HIF-1 activity using the mice carrying tumors with the HIF-1-dependent luciferase reporter gene. Furthermore, the intratumoral localization of (125)I-IPOS was examined by the autoradiographic study, and then the same slide was subjected to immunostaining for pimonidazole, which is the hypoxic marker. Results: The ratios of radioactivity in hypoxic cells to that in normoxic cells were more than 2. These results indicate incorporation of (125)I-IPOS into these cells and degradation of (125)I-IPOS by normoxic tumor cells. In the biodistribution study, (125)I-IPOS accumulated in the tumor (1.4 +/- 0.3 percentage injected dose per gram) 24 h after administration. At that time, (125)I-IPOS showed high tumor-to-blood and tumor-to-muscle ratios (5.1 +/- 0.3 and 14.0 +/- 3.9, respectively). The tumors were clearly visualized by in vivo imaging 24 h after (123)I-IPOS injection (tumor-to-muscle ratio was 9.6). The tumoral accumulation of (125)I-IPOS correlated with HIF-1 activity (R = 0.71, P < 0.05), and its intratumoral distribution coincided with the hypoxic regions. Conclusion: (123)I-IPOS is a potential probe for the imaging of HIF-1 activity in tumors. Given the role of HIF-1 in tumor biology, its detection may be considered an indicator of aggressive cancer phenotypes.
• New [¹¹C]phosgene based synthesis of [¹¹C]pyrimidines for positron emission tomography

  Koh Ichi Seki, Ken Ichi Nishijima, Kimihito Sanoki, Yuji Kuge, Masayuki Takahashi, Hiromichi Akizawa, Nagara Tamaki, Leonard I. Wiebe, Kazue Ohkura

  Heterocycles 77 (2) 1307 - 1321 0385-5414 2009/02/01 [Refereed][Not invited]
   

  Thymine, 5-FU, and uracil were successfully synthesized through a procedure involving a cyclocondensation of triphosgene with newly developed (α-substituted β-aminoacrylamides intermediates (1a, X= Me; 1b, X= F; 1c, X= H). The radioligands [2-11C]thymine and [2- 11C]5-fluorouracil were synthesized in high radiochemical yields in 16-17 minutes from the end of bombardment by applying the cyclocondensation method with [11C]COCl2. © 2009 The Japan Institute of Heterocyclic Chemistry All rights reserved.
• Myocardial beta-Adrenergic Receptor Density Assessed by (11)C-CGP12177 PET Predicts Improvement of Cardiac Function After Carvedilol Treatment in Patients with Idiopathic Dilated Cardiomyopathy

  Masanao Naya, Takahiro Tsukamoto, Koichi Morita, Chietsugu Katoh, Kenichi Nishijima, Hiroshi Komatsu, Satoshi Yamada, Yuji Kuge, Nagara Tamaki, Hiroyuki Tsutsui

  JOURNAL OF NUCLEAR MEDICINE 50 (2) 220 - 225 0161-5505 2009/02 [Refereed][Not invited]
   

  We evaluated whether myocardial P-adrenergic receptor (beta-AR) density, as determined by (11)C-CGP12177 PET, could predict improvement of cardiac function by P-blocker carvedilol treatment in patients with idiopathic dilated cardiomyopathy (IDC). Methods: Ten patients with IDC (left ventricular ejection fraction [LVEF] < 45%) were studied. Myocardial PAR density was estimated using (11)C-CGP12177 PET before treatment with carvedilol. Changes of LVEF in response to dobutamine infusion (ALVEF-dobutamine) were also measured by echocardiography. Changes of LVEF (Delta LVEF-carvedilol) were evaluated after 20 mo of carvedilol treatment. Results: Baseline myocardial PAR density significantly correlated with Delta LVEF-carvedilol (r = -0.88, P < 0.001). In contrast, Delta LVEF-clobutamine did not correlate with Delta LVEF-carvedilol (P = 0.65). Myocardial PAR density was the significant multivariate independent predictor of Delta LVEF-carvedilol (p = -0.88, P < 0.001) among univariate predictors, including functional class (r = 0.76, P < 0.05), plasma norepinephrine (r = 0.85, P < 0.01), LVEF (r = -0.64, P < 0.05), and age as confounding factors. Furthermore, myocardial PAR density was significantly correlated with plasma norepinephrine (r = -0.79, P < 0.01) and LVEF (r = 0.70, P < 0.05). Conclusion: Myocardial PAR density is more tightly related to improvement of LVEF-carvedilol than is cardiac contractile reserve in patients with IDC. Patients with decreased myocardial PAR have higher resting adrenergic drive, as reflected by plasma norepinephrine, and may receive greater benefit from being treated by antiadrenergic drugs.
• Mutual modulation between interleukin-10 and interleukin-6 induced by Rhodococcus aurantiacus infection in mice

  Yimin, Masashi Kohanawa, Michitaka Ozaki, Sanae Haga, Keiko Fujikawa, Songji Zhao, Yuji Kuge, Nagara Tamaki

  MICROBES AND INFECTION 10 (14-15) 1450 - 1458 1286-4579 2008/11 [Refereed][Not invited]
   

  The interaction between interleukin-10 (IL-10) and interleukin-6 (IL-6) was investigated in the inflammatory response to Rhodococcus aurantiacus (R. aurantiacus) infection, in which both cytokines act as anti-inflammatory cytokines. Compared with wild-type (WT) counterparts, IL-6 gene-deficient (IL-6(-)/(-)) mice mounted a more robust production of IL-10 and tumor necrosis factor-alpha (TNF-alpha) during the initial phase of infection. Administration of anti-IL-10 antibody resulted in all the mice dying within 3 days post-infection as well as a further elevated TNF-alpha release. In vitro challenge of the macrophages from IL-6(-)/(-) and WT mice with heat-killed R. aurantiacus also showed similar results. Addition of exogenous IL-6 depressed IL-10 and TNF-alpha production by either IL-6(-)/(-) mice or IL-6(-)/(-) mouse macrophages. Likewise, WT mouse macrophages pretreated with anti-IL-10 or anti-IL-6 antibody exhibited increased production of TNF-alpha and IL-6 or IL-10 respectively. Moreover, neutralization of both IL-10 and IL-6 induced a further increase in TNF-alpha production by WT mouse cells. Overall, we conclude that IL-10 is a key element in protecting mice against mortality, and that IL-10 and IL-6 production are negatively regulated by each other although they are additive in suppressing TNF-alpha release in R. aurantiacus-infected mouse model. (C) 2008 Elsevier Masson SAS. All rights reserved.
• Synthesis of a radioiodinated thymidine phosphorylase inhibitor and its preliminary evaluation as a potential SPECT tracer for angiogenic enzyme expression

  Masayuki Takahashi, Koh-ichi Seki, Ken-ichi Nishijima, Songji Zhao, Yuji Kuge, Nagara Tamaki, Kazue Ohkura

  JOURNAL OF LABELLED COMPOUNDS & RADIOPHARMACEUTICALS 51 (11-12) 384 - 387 0362-4803 2008/10 [Refereed][Not invited]
   

  The expression of thymidine phosphorylase (TP) is strongly associated with angiogenesis in tumors and activation of antitumor agents. We designed a novel 5-(125)I-labeled 6-(2-iminoimidazolidinyl)methyluracil hydrochloride ([(125)I]516IMUHCl) to develop an effective radiotracer for in vivo assessment of TIP expression in tumors and prognosis of cancer chemotherapy. Radiotracer synthesis was achieved by radioiodination of the precursor, 6-(2-iminoimidazolidinyl)methyluracil at the C-5 position with NCS/radioiodide. After purification by HPLC, [(125)I]56IMU-HCl was obtained in high radiochemical yield with satisfactory specific activity. The radiotracer showed high inhibitory potency for the target enzyme and good stability in vivo.
• Prolonged High-Fat Feeding Enhances Aortic F-18-FDG and Tc-99m-Annexin A5 Uptake in Apolipoprotein E-Deficient and Wild-Type C57BL/6J Mice

  Yan Zhao, Yuji Kuge, Songji Zhao, H. William Strauss, Francis G. Blankenberg, Nagara Tamaki

  JOURNAL OF NUCLEAR MEDICINE 49 (10) 1707 - 1714 0161-5505 2008/10 [Refereed][Not invited]
   

  F-18-FDG, a marker of the enhanced metabolism characteristic of activated inflammatory cells, and Tc-99m-annexin A5, a marker of apoptosis, are both widely believed to be useful for the imaging of unstable atheroma (rupture-prone vulnerable plaques [VP]). Serum cholesterol functions as a proinflammatory factor, driving the formation of VP, and affects the immune responses of aortic tissues systemically. It is therefore reasonable to postulate that prolonged cholesterol loading may alter the aortic uptake of these tracers. Here, we evaluated the aortic uptake of F-18-FDG and 99mTc-annexin A5 in apolipoprotein E-deficient (apoE(-/-)) and wild-type mice placed on high-fat diets. Methods: Male apoE(-/-) and wild-type (C57BU6J) mice were maintained on high-fat diets after the age of 5 wk. Wild-type mice fed regular chow were used as controls. At the ages of 10, 18, and 25 wk (5-15 mice per group at each time point), mice were injected with 18F-FDG or 99mTc-annexin A5 after 12 h of fasting. At 1 h after F-18-FDG injection (or 2 h after 99"'Tc-annexin A5 injection), mice were sacrificed, and the aortas were removed for well-type scintillation counting of radioactivity. The results were expressed as percentage injected dose per gram of tissue and normalized by animal body weight [(ID%/g) x kg]. En face staining was then performed to assess the location and size (surface area) of the lipid pool within each aortic specimen. Concurrent blood samples were obtained to determine the plasma lipid profile of each group. Results: No atherosclerotic lesions were found in wild-type mice regardless of the diet, whereas the lesion area progressively increased with age in apoE(-/-) mice. Mean plasma cholesterol levels remained stable with the regular diet in wild-type mice (73-78 mg/dL) but increased with cholesterol feeding in wild-type mice (143-179 mg/dL) and in apoE(-/-) mice (>1,300 mg/dL). Aortic tracer uptake [(ID%/g) x kg] remained stable with the regular diet in wild-type mice (0.054-0.053 and 0.021-0.023 for Tc-99m-annexin A5) but increased with cholesterol feeding in wild-type mice (0.164 for F-18-FDG and 0.036 for Tc-99m-annexin A5 at 25 wk) and in apoE(-/-) mice (0.249 for F-18-FDG and 0.047 for Tc-99m-annexin A5 at 25 wk). Conclusion: The accumulation of 18F-FDG and 99mTc-annexin A5 in aortic tissues is influenced not only by the progression of atherosclerotic disease but also by cholesterol loading overtime. Key Words: atherosclerosis; apoptosis; inflammation; serum cholesterol levels
• Targeting of Lectinlike Oxidized Low-Density Lipoprotein Receptor 1 (LOX-1) with (99m)TCLabeled Anti-LOX-1 Antibody: Potential Agent for Imaging of Vulnerable Plaque

  Seigo Ishino, Takahiro Mukai, Yuji Kuge, Noriaki Kume, Mikako Ogawa, Nozomi Takai, Junko Kamihashi, Masashi Shiomi, Manabu Minami, Toru Kita, Hideo Saji

  JOURNAL OF NUCLEAR MEDICINE 49 (10) 1677 - 1685 0161-5505 2008/10 [Refereed][Not invited]
   

  Lectinlike oxidized low-density lipoprotein (LDL) receptor 1 (LOX-1), a cell surface receptor for oxidized LDL, has been implicated in vascular cell dysfunction related to plaque instability, which could be a potential target for an atherosclerosis imaging tracer. In this study, we designed and prepared Tc-99m-labeled anti-LOX-1 monoclonal IgG and investigated its usefulness as an atherosclerosis imaging agent. Methods: Anti-LOX-1 monoclonal IgG and control mouse IgG2a were labeled with Tc-99m after derivatization with 6-hydrazinonicotinic acid to yield Tc-99m-LOX-1-mAb and Tc-99m-IgG2a, respectively. Myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHLMI) rabbits (atherosclerosis model) and control rabbits were injected intravenously with these probes, and in vivo planar imaging was performed. At 24 h after the injection, the aortas were removed, and radioactivity was measured. Autoradiography and histologic studies were performed with serial aortic sections. Results: The level of Tc-99m-LOX-1-mAb accumulation was 2.0-fold higher than the level of Tc-99m-IgG2a accumulation in WHHLMI rabbit aortas, and the level of Tc-99m-LOX-1-mAb accumulation in WHHLMI rabbit aortas was 10.0-fold higher than the level of Tc-99m-LOX-1-mAb accumulation in control rabbit aortas. In vivo imaging clearly visualized the atherosclerotic aortas of WHHLMI rabbits. Autoradiography and histologic studies revealed that regional Tc-99m-IgG2a accumulation was independent of the histologic grade of the lesions; however, regional Tc-99m-LOX1-mAb accumulation was significantly correlated with LOX-1 expression density and the vulnerability index. The highest level of 99mTc-LOX-1-mAb accumulation, expressed as {radioactivity in region of interest (Bq/mm(2))/[injected radioactivity (Bq)/animal body weight (g)]} x 102, was found in atheromatous lesions (3.8 +/- 1.1 [mean +/- SID]), followed in decreasing order by fibroatheromatous lesions (2.0 +/- 1.0), collagen-rich lesions (1.6 +/- 0.8), and neointimal lesions (1.4 (+/-) 0.7). Conclusion: The level of Tc-99m-LOX-1-mAb accumulation in grade IV atheroma was higher than that in neointimal lesions or other, more stable lesions. Nuclear imaging of LOX-1 expression with Tc-99m-LOX-1-mAb may be a useful means for predicting atheroma at high risk for rupture.
• SYNTHESIS OF C-11-LABELED URACIL DERIVATIVE FOR A PET TRACER TARGETING THYMIDINE PHOSPHORYLASE

  Masayuki Takahashi, Koh-ichi Seki, Ken-ichi Nishijima, Yuji Kuge, Nagara Tamaki, Kazue Ohkura

  HETEROCYCLES 76 (1) 237 - 241 0385-5414 2008/09 [Refereed][Not invited]
   

  The expression of thymidine phosphorylase (TP) is closely associated with angiogenesis in tumors. For developing a TP-expression-based positron emission tomography (PET) radiotracer for diagnosis and prognosis of cancer chemotherapy, we synthesized a novel C-11-labeled oxoimidazolidinylmethyluracil ([C-11]-2a), which was designed on the basis of one of the most potent inhibitors, 5-bromo-6-[(2-iminoimidazolidinyl)-methyl]uracil hydrobromide (5BIMU), through a ring closure reaction of [C-11]phosgene with a developed diamine precursor (1a). After purification by HPLC, the total synthesis was accomplished in just 23 min after bombardment, and the yield was 1653 MBq at the end of synthesis (EOS).
• Prominent lectin-like oxidized low density lipoprotein (LDL) receptor-1 (LOX-1) expression in atherosclerotic lesions is associated with tissue factor expression and apoptosis in hypercholesterolemic rabbits

  Yuji Kuge, Noriaki Kume, Scigo Ishino, Nozomi Takai, Yuki Ogawa, Takahiro Mukai, Manabu Minami, Masashi Shiomi, Hideo Saji

  BIOLOGICAL & PHARMACEUTICAL BULLETIN 31 (8) 1475 - 1482 0918-6158 2008/08 [Refereed][Not invited]
   

  Background: Despite increasing in vitro evidence that lectin-like oxidized low density lipoprotein (LDL) receptor-1 (LOX-1), a cell-surface receptor for oxidized LDL, is implicated in the atherogenesis and thrombus formation, its in vivo participation to the atherosclerotic plaque destabilization, rupture and thrombus formation remains unclear. Here, we compared the in vivo expression of LOX-1, with tissue factor (TF) expression and cell apoptosis, in atherosclerotic lesions of myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHLMI) rabbits. Methods and Results: We prepared sixty series of cross sections in the aortic arch and the thoracic aorta from four WHHLMI rabbits. LOX-1 and TF expression, as well as apoptotic events were determined by immunohistochemical staining and TUNEL methods, respectively. LOX-1 expression was mainly observed in the macrophage-rich lipid areas of vulnerable plaque-like atheromatous lesions where TF expression and apoptotic events were prominent. LOX-1 expression was positively correlated with TF expression (r=0.53, p<0.0001), apoptotic events (r=0.52, p<0.0001) and morphological vulnerability (r=0.63, p<0.0001). Conclusions: LOX-1 expression appears to be closely associated with TF expression, apoptotic events and the morphological vulnerability, suggesting the in vivo involvement of LOX-1 in the destabilization and rupture of atherosclerotic lesions and the subsequent thrombus formation. The present findings in hypercholesterolemic rabbits should help advance our understanding of the pathophysiology of atherosclerosis.
• PET 0-15 cerebral blood flow and metabolism after acute stroke in spontaneously hypertensive rats

  Takashi Temma, Yuji Kuge, Kohei Sano, Junko Kamihashi, Naoyuki Obokata, Hidekazu Kawashima, Yasuhiro Magata, Hideo Saji

  BRAIN RESEARCH 1212 18 - 24 0006-8993 2008/05 [Refereed][Not invited]
   

  Hypertension is a major stroke risk factor and is correlated with worse outcome after stroke. Thus, the effects of hypertension on cerebral hemodynamics and metabolism within an hour after stroke must be evaluated in detail. Cerebral blood flow (CBF), oxygen extraction fraction (OEF), cerebral metabolic rate for oxygen (CMRO2) and cerebral metabolic rate for glucose (CMRglc) were measured 1 h after the occlusion of the right middle cerebral artery (MCA) in male spontaneously hypertensive rats (SHR) and male normotensive Wistar Kyoto rats (WKY). Physiological responses were determined by positron emission tomography (PET) using O-15-H2O and radiolabeled O-15-O-2 blood (methodology previously developed in this laboratory) and by autoradiography (ARG) using F-18-FDG. The right hemisphere of SHR showed lower CBF values than the left hemisphere after stroke (right: 0.17 +/- 0.07 mL/min/g; left: 0.29 +/- 0.08 mL/min/g), CMRO2 (right: 2.55 +/- 0.80 mL/min/100 g; left: 4.11 +/- 0.84 mL/min/ 100 g) and CMRglc (right: 52.4 +/- 16.2 mg/min/100 g; left: 65.6 +/- 10.2 mg/min/100 g). WKY rats exhibited significant decreases only in CBF and CMRO2. These results suggest greater underlying physiologic disturbances in SHR. Also, the occlusion significantly reduced CBF in both hemispheres of SHR compared with WKY, suggesting a disturbance of the autoregulatory mechanism in SHR. In summary, our results indicate that hypertension intensifies metabolic disturbances after the onset of stroke, at least in the first hour. Therefore, we suggest that hypertension not only increases the incidence of stroke but also exacerbates stroke-mediated damage. (c) 2008 Elsevier B.V. All rights reserved.
• Heterogeneous reduction of myocardial oxidative metabolism in patients with ischemic and dilated cardiomyopathy using C-11 acetate PET

  Yen-Wen Wu, Masanao Naya, Takahiro Tsukamoto, Hiroshi Komatsu, Koichi Morita, Keiichiro Yoshinaga, Yuji Kuge, Hiroyuki Tsutsui, Nagara Tamaki

  CIRCULATION JOURNAL 72 (5) 786 - 792 1346-9843 2008/05 [Refereed][Not invited]
   

  Background The C-11-acetate positron emission tomography can estimate myocardial oxidative metabolism, but previous studies have only evaluated small populations and the difference between ischemic (ICM) and idiopathic dilated cardiomyopathy (DCM) has not been fully investigated. The present aims were to evaluate global and regional myocardial oxidative metabolism in a well-characterized, large population with left ventricular (LV) dysfunction in order to clarify the metabolic differences between ICM and DCM. Methods and Results Seventy-eight patients with ejection fraction (EF) <= 50% (33 ICM; 45 DCM) were compared with 14 healthy controls. Myocardial oxidative metabolism was estimated with a clearance rate constant (Kmono) and the coefficient of variation (CV) of regional Kmono. Patients with LV dysfunction had reduced Kmono and higher CV (p<0.05). In the comparison of oxidative alterations with clinical variables there was a weak correlation between Kmono and LVEF (r=0.27). Although Kmono was reduced in both ICM and DCM, CV was more pronouncedly increased in ICM (p=0.001). In multivariate analysis, the presence of left bundle branch block (LBBB) was an independent predictor of heterogeneous oxidative metabolism in DCM (R-2=0.30, p<0.0001). Conclusions Global reduction of myocardial oxidative metabolism occurred in both ICM and DCM. Heterogeneous oxidative metabolism was observed in these patients, especially those with ICM. Furthermore, LBBB was the independent predictor of heterogeneous oxidative metabolism inpatients with DCM.
• Evaluation of radioiodinated (2S,alpha S)-2-(alpha-(2-iodophenoxy)benzyl) morpholine as a radioligand for imaging of norepinephrine transporter in the heart

  Yasushi Kiyono, Taku Sugita, Masashi Ueda, Hidekazu Kawashima, Naoki Kanegawa, Yuji Kuge, Yasuhisa Fujibayashi, Hideo Saji

  NUCLEAR MEDICINE AND BIOLOGY 35 (2) 213 - 218 0969-8051 2008/02 [Refereed][Not invited]
   

  Introduction: The norepinephrine transporter (NET) is located presynaptically on noradrenergic nerve terminals and plays a critical role in the regulation of the synaptic norepinephrine (NE) concentration via the reuptake of NE. Changes in NET have been recently reported in several cardiac failures. Therefore, a NET-specific radioligand is useful for in vivo assessment of changes in NET density in various cardiac disorders. Recently, we developed a radioiodinated reboxetine analogue, (2S,alpha S)-2-(alpha-(2-iodophenoxy)benzyl)morpholine ((S,S)-IPBM), for NET imaging. In the current study, we assessed the applicability of radioiodinated (S,S)-IPBM to NET imaging in the heart. Methods: The NET affinity and selectivity were measured from the ability to di splace specific [(3)H]nisoxetine and (S,S)-[(125)I]IPBM binding to rat heart membrane, respectively. To evaluate the distribution of (S,S)-[(125)I]IPBM in vivo, biodistribution experiment was performed in rats. With the use of several monoamine transporter binding agents, pharmacological blocking experiments were performed in rats. Results: In vitro binding assays showed that the affinity of (S,S)-IPBM to NET was similar to those of the well-known NET-specific binding agents, nisoxetine and desipramine. Furthermore, (S,S)-[(125)I]IPBM binding was inhibited by nisoxetine and desipramine, but not by dopamine or serotonin transporter binding agents. These data indicated that (S,S)-IPBM had high affinity and selectivity for NET in vitro. Biodistribution studies in rats showed rapid and high uptake of (S,S)-[(125)I]IPBM by the heart and rapid clearance from the blood. The heart-to-blood ratio was 31.9 at 180 min after the injection. The administration of nisoxetine and desipramine decreased (S,S)-[(125)I]IPBM accumulation in the heart, but injection of fluoxetine and GBR12909 had little influence. Conclusions: Radioiodinated (S,S)-IPBM is a potential radioligand for NET imaging in the heart. (c) 2008 Elsevier Inc. All rights reserved.
• Usefulness of C-11-methionine for differentiating tumors from granulomas in experimental rat models: A comparison with F-18-FDG and F-18-FLT

  Songji Zhao, Yuji Kuge, Masashi Kohanawa, Toshiyuki Takahashi, Yan Zhao, Min Yi, Kakuko Kanegae, Koh-ichi Seki, Nagara Tamaki

  JOURNAL OF NUCLEAR MEDICINE 49 (1) 135 - 141 0161-5505 2008/01 [Refereed][Not invited]
   

  Many clinical PET studies have shown that increased F-18-FDG uptake is not specific to malignant tumors. F-18-FDG is also taken up in inflammatory lesions, particularly in granulomatous lesions such as sarcoidosis or active inflammatory processes after chemoradiotherapy, making it difficult to differentiate malignant tumors from benign lesions, and is the main source of false-positive F-18-FDG PET findings in oncology. These problems may be overcome by multitracer studies using 3'-deoxy-3'-F-18-fluorothymidine (F-18-FLT) or L-C-11-methionine. However, F-18-FLT or C-11-methionine uptake in granulomatous lesions remains unclarified. In this study, the potentials of F-18-FLT and C-11-methionine in differentiating malignant tumors from granulomas were compared with F-18-FDG using experimental rat models. Methods: Dual-tracer tissue distribution studies using 18F-FDG and H-3-FLT (groups I and III) or F-18-FDG and C-11-methionine (groups II and IV) were performed on rats bearing both granulomas (Mycobacterium bovis bacillus Calmette-Guerin [BCG]-induced) and hepatomas (KDH-8-induced) (groups I and II) or on rats bearing both turpentine oil-induced inflammation and hepatomas (groups III and IV). One hour after the injection of a mixture of F-18-FDG and H-3-FLT or of F-18-FDG and C-14-methionine, tissues were excised to determine the radioactivities of F-18-FDG, H-3-FLT, and C-14-methionine (differential uptake ratio). Results: Mature epithelioid cell granuloma formation and massive lymphocyte infiltration were observed in the granuloma tissue induced by BCG, histologically similar to sarcoiclosis. The granulomas showed high F-18-FDG uptake comparable to that in the hepatomas (group I, 8.18 +/- 2.40 vs. 9.13 +/- 1.52, P = NS; group II, 8.43 +/- 1.45 vs. 8.91 +/- 2.32, P = NS). C-14-Methionine uptake in the granuloma was significantly lower than that in the hepatoma (1.31 +/- 0.22 vs. 2.47 +/- 0.60, P < 0.01), whereas H-3-FLT uptake in the granuloma was comparable to that in the hepatoma (1.98 +/- 0.70 vs. 2.30 +/- 0.67, P = NS). Mean uptake of F-18-FDG, H-3-FLT, and C-14-methionine was markedly lower in the turpentine oil-induced inflammation than in the tumor. Conclusion: C-14-Methionine uptake was significantly lower in the granuloma than in the tumor, whereas F-18-FDG and H-3-FLT were not able to differentiate granulomas from tumors. These results suggest that C-14-methionine has the potential to accurately differentiate malignant tumors from benign lesions, particularly granulomatous lesions, providing a biologic basis for clinical PET studies.
• Extensive FDG uptake and its modification with corticosteroid in a granuloma rat model: an experimental study for differentiating granuloma from tumors

  Songji Zhao, Yuji Kuge, Masashi Kohanawa, Toshiyuki Takahashi, Hidekazu Kawashima, Takashi Temma, Toshiki Takei, Yan Zhao, Koh-ichi Seki, Nagara Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 34 (12) 2096 - 2105 1619-7070 2007/12 [Refereed][Not invited]
   

  Introduction Increased F-18-fluorodeoxyglucose (FDG) uptake in inflammatory lesions, particularly in granulomatous inflammation (e.g., sarcoidosis), makes it difficult to differentiate malignant tumors from benign lesions and is the main source of false-positive FDG-PET findings in oncology. Here, we developed a rat granuloma model and examined FDG uptake in the granuloma. The effects of corticosteroid on FDG uptake in the granuloma were compared with those in a malignant tumor. Methods Rats were inoculated with Mycobacterium bovis bacillus Calmette-Guerin (BCG) or allogenic hepatoma cells, and subdivided into control and pretreated (methylprednisolone acetate, 8 mg/kg i.m.) groups. Radioactivity in tissues was determined 1 h after the FDG injection. FDG-PET was performed in rats bearing BCG granulomas or tumors before and after prednisolone treatment. Results Mature epithelioid cell granuloma-formation and massive lymphocyte-infiltration were observed in the control group of granuloma, histologically similar to sarcoidosis. The mean FDG uptake in the granuloma was comparable to that in the hepatoma. Prednisolone reduced epithelioid cell granuloma-formation and lymphocyte-infiltration. Prednisolone significantly decreased the level of FDG uptake in the granuloma (52% of control), but not in the hepatoma. The FDG uptake levels in the granulomas and tumors were clearly imaged with PET. Conclusion We developed an intramuscular granuloma rat model that showed a high FDG uptake comparable to that of the tumor. The effect of prednisolone pretreatment on FDG uptake was greater in the granuloma than in the tumor. These results suggest that BCG-induced granuloma may be a valuable model and may provide a biological basis for FDG studies.
• Decreased myocardial beta-adrenergic receptor density in relation to increased sympathetic tone in patients with nonischemic cardiomyopathy

  Takahiro Tsukamoto, Koichi Morita, Masanao Naya, Masayuki Inubushi, Chietsugu Katoh, Kenichi Nishijima, Yuji Kuge, Hiroshi Okamoto, Hiroyuki Tsutsui, Nagara Tamaki

  JOURNAL OF NUCLEAR MEDICINE 48 (11) 1777 - 1782 0161-5505 2007/11 [Refereed][Not invited]
   

  Cardiac sympathetic function plays an important role in the regulation of left ventricular (LV) function and the pathophysiology of LV dysfunction. C-11-CGP-12177 (C-11-CGP) has been used to assess myocardial beta-adrenergic receptor (P-AR) density in vivo using PET. The aim of this study is to measure myocardial P-AR density in patients with nonischemic cardiomyopathy and to compare the measurements with various standard parameters of heart failure (HF), particularly with presynaptic function assessed by I-123-metaiodobenzy(guanidine (I-123-MIBG) imaging. Methods: C-11-CGP PET was performed on 16 patients with nonischemic cardiomyopathy and 8 age-matched healthy volunteers using a double injection method. A C-11-CGP dynamic scan for 75 min was performed after the injection of C-11-CGP with a high specific activity. After 30 min, C-11-CGP with a low specific activity was injected. The P-AR density of the whole LV was calculated on the basis of the graphical analysis method. Additionally, beta-AR density was compared with LV ejection fraction (LVEF), sympathetic presynaptic function assessed using I-123-MIBG kinetics, and neurohormonal parameters. Results: The P-AR density of patients was significantly lower than that of healthy volunteers (3.80 +/- 0.96 vs. 7.70 +/- 1.92 pmol/mL; P < 0.0001). In the patients, P-AR density correlated significantly with LVEF (r = 0.62, P < 0.05). Furthermore, P-AR density correlated significantly with the I-123-MIBG washout rate (r = -0.68, P < 0.01) and delayed heart-to-mediastinum ratio (H/M ratio) (r = 0.61, P < 0.05). On the other hand, the correlation between P-AR density and early H/M ratio was not significant (r = 0.40, P = 0.13). The beta-AR density of patients with severe HF (New York Heart Association functional [NYHA] class III) was significantly lower than that of those with NYHA functional class I or class II HIF (3.24 +/- 0.96 vs. 4.24 +/- 0.73 pmol/mL; P < 0.05). Conclusion: A reduction in P-AR density measured by C-11-CGP PET was observed in patientswith nonischemic cardiomyopathy. This downregulation may be due to the increased presynaptic sympathetic tone as assessed by I-123-MIBG imaging.
• Comparison of Tc-99m-annexin A5 with F-18-FDG for the detection of atherosclerosis in ApoE-/- mice

  Yan Zhao, Yuji Kuge, Songji Zhao, Koichi Morita, Masayuki Inubushi, H. William Strauss, Francis G. Blankenberg, Nagara Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 34 (11) 1747 - 1755 1619-7070 2007/11 [Refereed][Not invited]
   

  Purpose Tc-99m-annexin A5, a marker of ongoing apoptosis, and F-18-FDG, a marker of the increased metabolism of inflammatory cells, are supposed to be useful in the detection of metabolically active atheroma. This study reports a comparison of the intralesional distribution of these tracers in relation to lesion development in ApoE-/- mice. Methods Male ApoE-/- mice (n = 12-14/group) were maintained on a Western-type diet after the age of 5 weeks. At 25 weeks, 99mTc-annexin A5 or 18F-FDG was injected and the aortas were harvested for autoradiography (ARG) and Oil Red O staining. Regional radioactivity accumulation was compared in relation to the Oil Red O staining score (ranging from 0 to 3, a semiquantitative parameter for evaluating lesion development). Results Both Tc-99m-annexin A5 and 18F-FDG showed preferential uptake into atherosclerotic lesions, with higher uptake levels for 18F-FDG ( mean, 56.07 % ID x kg/m(2)) than for Tc-99m-annexin A5 (mean, 10.38 % ID x kg/m2). The regional uptake levels of each tracer correlated with the Oil Red O staining score (r = 0.65, p<0.05 for Tc-99m-annexin A5; r=0.56, p<0.05 for 18F-FDG). The uptake ratios of advanced lesions ( score >0.5) to early lesions ( score <0.5) were significantly higher for Tc-99m-annexin A5 than for F-18-FDG (f = 4.73, p=0.03). Conclusion Both Tc-99m-annexin A5 and 18F-FDG accumulate in atherosclerotic lesions and correlate with the severity of each lesion. The higher absolute uptake levels of F-18-FDG may be advantageous for lesion detection, whereas the preferential uptake of 99mTc-annexin A5 in advanced lesions may be a useful indicator of late-stage lesions or vulnerable plaque transformation.
• Lectin-like oxidized LDL receptor-1 (LOX-1) expression is associated with atherosclerotic plaque instability-analysis in hypercholesterolemic rabbits

  Seigo Ishino, Takahiro Mukai, Noriaki Kume, Daigo Asano, Mikako Ogawa, Yuji Kuge, Manabu Minami, Toru Kita, Masashi Shiomi, Hideo Saji

  ATHEROSCLEROSIS 195 (1) 48 - 56 0021-9150 2007/11 [Refereed][Not invited]
   

  Lectin-like oxidized LDL receptor-1 (LOX-1), a cell-surface receptor for oxidized LDL (Ox-LDL), has been implicated in vascular cell dysfunction related to atherosclerotic plaque instability, according to cell culture experiments. In the present study, we investigated the relationship between LOX-1 expression and plaque instability in hypercholesterolemic rabbits by immunohistological analyses in vivo. We prepared thirty series of cross sections of the thoracic aorta from six myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHLMI) rabbits (12-24 months), in which seventy atherosclerotic plaques were observed. LOX-1, matrix metal loproteinase-9 (MMP-9), monocyte chemoattractant protein-1 (MCP-1) expression, apoptotic events, plaque instability index (an index of the morphological destabilization of atherosclerotic plaques) and fibromuscular cap thickness in each atherosclerotic plaque were determined by immunohistochemical staining, TUNEL staining and Azan-Mallory staining. LOX-1 expression was positively correlated with the plaque instability index and MMP-9 expression. LOX-1 expression was more prominent in atherosclerotic plaques with thinner fibromuscular cap (< 100 mu m). Furthermore, LOX-1 expression was shown in the macrophage-rich lipid core area where MCP-1 expression and apoptotic events were prominent. These results indicate that enhanced LOX-1 expression was associated with histologically unstable atherosclerotic plaques in hypercholesterolemic rabbits, suggesting the involvement of LOX-1 in the destabilization of atherosclerotic plaques in vivo. (c) 2006 Elsevier Ireland Ltd. All rights reserved.
• All-trans retinoic acid enhances murine dendritic cell migration to draining lymph nodes via the balance of matrix metalloproteinases and their inhibitors

  Stephanie Darmanin, Jian Chen, Songji Zhao, Hongyan Cui, Reza Shirkoohi, Naoki Kubo, Yuji Kuge, Nagara Tamaki, Koji Nakagawa, Jun-Ichi Hamada, Tetsuya Moriuchi, Masanobu Kobayashi

  JOURNAL OF IMMUNOLOGY 179 (7) 4616 - 4625 0022-1767 2007/10 [Refereed][Not invited]
   

  Cancers escape immune surveillance through the manipulation of the host's immune system. Sequestration of dendritic cells (DCs) within tumor tissues and the subsequent inhibition of their migration is one of the several mechanisms by which tumors induce immmosuppression. In view of recent findings depicting the improvement of tumor immune responses in cancer patients following all-trans retinoic acid (ATRA) treatment, we sought to identify the effects of ATRA on DC mobility in the context of tumor immunotherapy. Our results demonstrate that ATRA, added to differentiating murine bone marrow progenitor cells, enhances the invasive capacity of the resulting DCs. Immature DCs injected intratumorally in mice show increased accumulation in draining lymph nodes, but not in nondraining lymph nodes and spleens, when differentiated in the presence of ATRA. The in vitro migration of mature DCs through the basement membrane matrix toward the lymphoid chemokines CCL19 and CCL21 is enhanced in these cells, albeit not in the presence of a matrix metalloproteinase (MMP) inhibitor. An increase in MMP production with a simultaneous decrease in the production of their inhibitors (tissue inhibitors of matrix metalloproteinase or TIMPs) is provoked by ATRA. This affects the MMP/TIMP balance in DCs, in particular that of MMP-9 and TIMP-1, favoring protease activity and thus allowing for enhanced DC mobilization. In conclusion, this study demonstrates that ATRA is capable of improving DC trafficking in a tumor milieu and, in view of the encouraging results obtained in the clinic, further supports the notion that ATRA might be a valuable chemical adjuvant to current immunotherapeutic strategies for cancer.
• Distribution profiles of membrane type-1 matrix metalloproteinase (MT1-MMP), matrix metalloproteinase-2 (MMP-2) and cyclooxygenase-2 (COX-2) in rabbit atherosclerosis: Comparison with plaque instability analysis

  Yuji Kuge, Nozomi Takai, Seigo Ishino, Takashi Temma, Masashi Shiomi, Hideo Saji

  Biological and Pharmaceutical Bulletin 30 (9) 1634 - 1640 0918-6158 2007/09 [Refereed][Not invited]
   

  Background: Despite increasing evidence that membrane type 1 matrix metalloproteinase (MT1-MMP), matrix metalloproteinase-2 (MMP-2), and cyclooxygenase-2 (COX-2) are involved in the pathogenesis of atherosclerosis, the possible links among these enzymes remain unclear. Accordingly, we investigated the distribution of MT1-MMP, MMP-2, and COX-2 immunohistologically in the atherosclerotic lesions of hypercholesterolemic (WHHLMI) rabbits. Methods and Results: Distribution of MT1-MMP, MMP-2, and COX-2 was examined by immunohistochemical staining using sixty cross sections of the ascending-arch and thoracic aortas prepared from 4 WHHLMI rabbits. MT1-MMP and MMP-2 staining was prominently observed in the macrophage-rich regions of the atheromatous lesions, and was positively correlated with morphological vulnerability (r=0.63 for MT1-MMP r=0.60 for MMP-2 p< 0.0001). MT1-MMP staining was positively correlated with MMP-2 staining (r=0.61, p< 0.0001). COX-2 staining was also the highest in the macrophage-rich regions of the atheromatous lesions, with relatively high staining levels in other more stable lesions. Conclusions: Co-distribution of MT1-MMP, MMP-2, and COX-2 was demonstrated in grade IV atheroma, indicating a possible link among these enzymes in the destabilization of atherosclerotic plaques. The relatively high COX-2 distribution in other more stable lesions may indicate its additional roles in the stabilization of atherosclerotic lesions. The present findings in hypercholesterolemic rabbits should help advance our understanding of the pathophysiology of atherosclerosis and provide useful information for the development of new therapeutic and diagnostic (imaging) agents that target MMPs and COX-2 in atherosclerosis. © 2007 Pharmaceutical Society of Japan.
• Applicability of a high-resolution small semiconductor gamma camera to small animal imaging

  Yasushi Kiyono, Yuji Kuge, Yumiko Katada, Hidekazu Kawashima, Yasuhiro Magata, Hideo Saji

  NUCLEAR MEDICINE COMMUNICATIONS 28 (9) 736 - 741 0143-3636 2007/09 [Refereed][Not invited]
   

  Objective Recently, small semiconductor gamma cameras (SSGCs) with high resolution and sensitivity, which are much more convenient to use as compared with SPELT and PET, have been developed for mapping the sentinel lymph node. The high resolution and sensitivity of the SSGCs may make them useful for small animal imaging. Therefore, we assessed the applicability of the SSGC to small animal imaging using a rat model of focal cerebral ischaemia. Methods The right middle cerebral artery (MLA) of anaesthetized rats was occluded intraluminally with a nylon monofilament. Twenty-four hours after the occlusion, Tc-99m-HMPAO (3.7 MBq) was injected and a static acquisition (5 min) was performed using the SSGC. Regions of interest (ROls) were set on each hemisphere of the horizontal brain images. After the acquisition, the brains were removed and the radioactivity in each hemisphere was measured using an NaI scintillation counter. Results Reduced CBF in the right MCA territory was clearly visualized with the SSGC in vivo. The radioactivity in the ROls determined by the SSGC was significantly correlated with that determined by the ex vivo counting method (P<0.001, R-2=0.74). Furthermore, in both of the in-vivo imaging and ex-vivo counting methods, the right to left count ratio (R/L ratio) was significantly lower in the MLA-occluded rats than that in normal rats (MLA-occluded rats: 0.77 +/- 0.08, normal rats: 1.01 +/- 0.07, P<0.005). Conclusions The SSGC clearly visualized and quantitatively detected the reduced CBF in MLA-occluded rats. Furthermore, these high resolution and sensitivity of SSGC can avoid the disadvantage of small animal imaging with PET and SPELT, such as a large mass injected tracer and the exposure of investigators to radiation. Thus, the high resolution and sensitivity of the SSGC make it useful for small animal imaging.
• Development of a novel neodymium compound for in vivo fluorescence imaging

  Kazuki Aita, Takashi Temma, Yuji Kuge, Hideo Saji

  LUMINESCENCE 22 (5) 455 - 461 1522-7235 2007/09 [Refereed][Not invited]
   

  We developed a novel fluorescent probe that contains the neodymium(III) complex moiety and fluorescein moiety. This probe can emit long-lived near-infrared luminescence derived from a Nd ion through excitation of the fluorescein moiety with visible light (lambda(ex) = 488 nm, lambda(em) = 880 nm, lifetime = 2.3 mu s). These results indicate the possibility of the probe as a candidate for in vivo fluorescence molecular imaging. Copyright (C) 2007 John Wiley & Sons, Ltd.
• Comparison of MET-PET and FDG-PET for differentiation between benign lesions and lung cancer in pneumoconiosis

  Kakuko Kanegae, Ikuo Nakano, Kiyonobu Kimura, Hiroshi Kaji, Yuji Kuge, Tohru Shiga, Songji Zhao, Shouzo Okamoto, Nagara Tamaki

  ANNALS OF NUCLEAR MEDICINE 21 (6) 331 - 337 0914-7187 2007/08 [Refereed][Not invited]
   

  Objective The aim of this study was to evaluate and compare the ability of C-11-methionine (MET) and F-18 fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) to diagnose lung cancer in patients with pneumoconiosis. Methods Twenty-six subjects underwent both whole-body MET-PET and FDG-PET on the same day. The first group was a lung cancer group, which consisted of 15 patients, and included those with pneumoconiosis with increased nodules (13 cases), hemoptysis (I case), and positive sputum cytology (I case). The second group was a no-malignancy control group, consisting of I I patients with pneumoconiosis. Results Sianificant correlations between nodule size and the maximum standardized uptake value (SUVmax) of the two PET tracers were observed in the control group. The larger the nodule size, the greater were the amounts of these tracers accumulated (MET: r = 0.771, P < 0.0001; FDG: r = 0.903, P < 0.0001). The SUVmax of MET was significantly lower than that of FDG in the pneumocomotic nodules (P < 0.0001). Lung cancer was found in 5 of 19 nodules (two with adenocarcinoma, one with squamous cell carcinoma, one with small cell carcinoma, and one with large cell carcinoma) in the first group. As for nodules equal to or less than 3 cm in diameter, the SUVmax of MET was significantly higher in the lung cancer than in the pneumoconiotic nodules, with 3.48 +/- 1.18 (mean SE) for the lung cancer and 1.48 +/- 0.08 for the pneumoconiotic nodules (P < 0.01), similar to the SUVmax of FDG, with 7.12 +/- 2.36 and 2.85 +/- 0.24 (P < 0.05), respectively. On the basis of the criteria for the control group, FDG and MET identified lung cancer with sensitivities of 60% and 80%, specificities of 100% and 93%, accuracies of 90% and 90%, positive predictive values of 100% and 80%, and negative predictive values of 88% and 93%, respectively. Conclusions Our results indicate that nodules with an intense uptake of MET and FDG relative to their size should be carefully observed because of a high risk for lung cancer.
• Tc-99m-Annexin A5 for noninvasive characterization of atherosclerotic lesions: imaging and histological studies in myocardial infarction-prone Watanabe heritable hyperlipidemic rabbits

  Seigo Ishino, Yuji Kuge, Nozomi Takai, Nagara Tamaki, H. William Strauss, Francis G. Blankenberg, Masashi Shiomi, Hideo Saji

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 34 (6) 889 - 899 1619-7070 2007/06 [Refereed][Not invited]
   

  Apoptosis is commonly observed in advanced atherosclerotic lesions. Tc-99m-annexin A5 (Tc-99m-annexin V) has been proposed as a potential tracer for imaging apoptosis in atherosclerotic plaques. Accordingly, we determined the usefulness of Tc-99m-annexin A5 as an atherosclerosis imaging tracer in a rabbit model (myocardial infarction-prone Watanabe heritable hyperlipidemic rabbits; WHHLMI rabbits) of spontaneous atherosclerosis. Methods The WHHLMI and control rabbits were injected intravenously with Tc-99m-annexin A5. After in vivo planar imaging, the radioactivity in the aorta was measured. Autoradiography, TUNEL staining, Azan-Mallory staining and immunohistological studies were performed serially throughout the aorta. Results Tc-99m-Annexin A5 accumulation in the aorta of the WHHLMI rabbits was 5.6-fold higher than in that of control rabbits. Autoradiography showed heterogeneous multifocal accumulation of Tc-99m-annexin A5 in WHHLMI rabbits. Tc-99m-Annexin A5 accumulation was highest in the atheromatous lesions (6.2 +/- 2.5, %IDxBW/mm(2) 10(3)), followed in decreasing order by neointimal (4.9 +/- 1.3), fibroatheromatous (4.5 +/- 1.9), and collagen-rich lesions (3.3 +/- 1.4). The regional Tc-99m-annexin A5 accumulation was significantly correlated with the TUNEL-positive cell density, macrophage density and "vulnerability index," an index of the morphological destabilized characteristics. The in vivo imaging clearly visualized the atherosclerotic lesions in WHHLMI rabbits. Conclusion The present study in WHHLMI rabbits showed higher Tc-99m-annexin A5 accumulation in grade IV atheroma than in other more stable lesions. Tc-99m-Annexin A5 may be useful in identifying atheroma that is at higher risk for rupture and possibly in assessing the response to anti-atherosclerotic therapy.
• A novel and efficient synthesis of [2-C-11]5-fluorouracil for prognosis of cancer chemotherapy

  Koh-ichi Seki, Ken-ichi Nishijima, Yuji Kuge, Nagara Tamaki, Leonard I. Wiebe, Kazue Ohkura

  JOURNAL OF PHARMACY AND PHARMACEUTICAL SCIENCES 10 (2) 212 - 216 1482-1826 2007/06 [Refereed][Not invited]
   

  Purpose: In order to facilitate the use of the PET- based ' Strauss test' for 5- FU sensitivity, a rapid and facile synthesis of [ 2-C-11] 5- fluorouracil ([ 2- C-11] 5- FU), based on [ C-11] phosgene ([ C-11] COCl2), is reported. Methods: The key intermediate ( E)-beta- benzoylamino- alpha- fluoroacrylamide ( 1) and [ C-11] phosgene was submitted to cyclo-condensation to give [ 2- C-11] 5- fluorouracil. Results: [ 2- C-11] 5- Fluorouracil was synthesized in 17 min with high (similar to 25%) radiochemical yield. Conclusion: The present study provides a rapid, simple, and efficient synthesis of [ 2- C-11] 5- FU, that would serve as a useful prognostic PET tracer for 5- FU chemotherapy.
• Is MIBG a substrate of P-glycoprotein?

  Yasushi Kiyono, Tomoko Yamashita, Hisako Doi, Yuji Kuge, Toshiya Katsura, Ken-Ichi Inui, Hideo Saji

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 34 (4) 448 - 452 1619-7070 2007/04 [Refereed][Not invited]
   

  Purpose Radionuclide therapy with I-131-labelled meta-iodobenzylguanidine ([I-131]MIBG) is effective in cases where it is difficult to carry out surgical resection or debulking of neuroendocrine tumours (NETs). However, it has recently been reported that P-glycoprotein (P-gp) is expressed in these NETs. Therefore, it is important to clarify whether MIBG is a substrate of P-gp or not. In this study, using a human cell line which overexpresses P-gp, LLC-GA5-COL150, we investigated this question. Methods The transcellular transport and accumulation of [I-125]MIBG were measured using monolayer cultures grown in Transwell chambers. [I-125]MIBG was added to either the basolateral or the apical side, aliquots of the incubation medium on the other side were taken at specified times, and the radioactivity was measured. For accumulation experiments, the cells on the filters were solubilised and the radioactivity in aliquots was measured. Results There were no significant differences in the transport of MIBG between LLC-PK1 and LLC-GA5-COL150 monolayers in either direction until 60 min. With respect to the accumulation of MIBG, there were no significant differences between LLC-PK1 and LLC-GA5-COL150 cells in either direction. Conclusion MIBG is not a substrate of P-gp. Therefore, radionuclide therapy with MIBG would be useful in the treatment of NETs expressing P-gp.
• Smoking cessation normalizes coronary endothelial vasomotor response assessed with O-15-water and PET in healthy young smokers

  Koichi Morita, Takahiro Tsukamoto, Masanao Naya, Kazuyuki Noriyasu, Masayuki Inubushi, Tohru Shiga, Chietsugu Katoh, Yuji Kuge, Hiroyuki Tsutsui, Nagara Tamaki

  JOURNAL OF NUCLEAR MEDICINE 47 (12) 1914 - 1920 0161-5505 2006/12 [Refereed][Not invited]
   

  Cigarette smoking is one of the risk factors of cardiovascular diseases and is related to abnormal peripheral and coronary vascular vasomotion. Coronary vascular endothelial dysfunction is caused by chronic smoking in smokers without epicardial coronary artery stenosis. The coronary endothelial vasomotion abnormality is restored by interventions such as L-arginine or vitamin C infusion. However, to our knowledge, the effect of smoking cessation on coronary vasomotor response has not been elucidated. Therefore, the aim of this study was to assess the effect of smoking cessation on coronary vasomotor response by quantitative myocardial blood flow (MBF) measurement using O-15-water and PET. Methods: Fifteen young smokers (Brinkman index > 100; mean age +/- SD, 26 +/- 4 y) with no evidence of heart disease or cardiovascular risk factors, except for smoking, and age-matched nonsmokers (n = 12) were enrolled in this study. MBF was measured at rest, during the cold pressor test (CPT), before and at 1 and 6 mo after smoking cessation. In addition, MBF measurement during adenosine triphosphate (ATP) infusion was performed before and at 6 mo after smoking cessation. In nonsmokers, MBF was measured at rest, during ATP infusion, and during the CPT. Results: MBF at rest and during ATP infusion did not differ between smokers and nonsmokers (0.73 +/- 0.12 vs. 0.80 +/- 0.15 mLg/min and 3.15 +/- 1.43 vs. 3.69 +/- 0.76 mL/g/min, respectively; P = not significant). In contrast, MBF during the CPT in smokers was lower than that in nonsmokers (0.90 +/- 0.19 vs. 1.12 +/- 0.28 mUg/min; P < 0.05). There was no significant difference in MBF either at rest or during ATP infusion between before and after smoking cessation, but MBF during the CPT increased at 1 mo in comparison with before cessation of smoking (0.90 +/- 0.19 vs. 1.02 +/- 0.22 mUg/min; P < 0.01). An improvement of MBF response to the CPT was preserved at 6 mo after smoking cessation. Conclusion: Coronary vasomotor abnormality assessed by MBF response to the CPT was improved at 1 mo after smoking cessation. These findings indicate that coronary endothelial dysfunction may be reversible within 1 mo after smoking cessation in healthy young smokers.
• Photochemical synthesis of polycyclic pyrimidines through the acid catalyzed cycloaddition of 6-chloro-1-methyluracil to methyl substituted benzenes

  Kazue Ohkura, Takeshi Yamaguchi, Ken-ichi Nishijima, Yuji Kuge, Koh-ichi Seki

  HETEROCYCLES 70 501 - + 0385-5414 2006/12 [Refereed][Not invited]
   

  UV-irradiation of 6-chloro-l-methyluracil with benzene in the presence of TFA resulted in 1,2-cycloaddition and susequent elimination of HCl gave a cyclooctapyrimidine-2,4-dione. Similar acid catalyzed photoreaction with substituted benzenes bearing two or three methyl groups afforded the corresponding cyclooctapyrimidines and two novel pentacyclic compounds, 9,11-diazapentacyclo[6.4.0.0(1,3).0(2,5).0(4,8)]dodecanes and 9.11diazapentacyclo[6.4.0.0(1,3).0(2,6).0(4,8)]dodcanes, in fair yields.
• Estimation of oxygen metabolism in a rat model of permanent ischemia using positron emission tomography with injectable O-15-O-2

  Takashi Temma, Yasuhiro Magata, Yuji Kuge, Sayaka Shimonaka, Kohei Sano, Yumiko Katada, Hidekazu Kawashima, Takahiro Mukai, Hiroshi Watabe, Hidehiro Iida, Hideo Saji

  JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM 26 (12) 1577 - 1583 0271-678X 2006/12 [Refereed][Not invited]
   

  The threshold of cerebral blood flow (CBF) into infarction in rats has been indicated to be similar to that in patients. However, CBF does not reflect metabolic function, and so estimations of oxygen metabolism have been required. Here, we estimated changes in oxygen metabolism after occluding the right middle cerebral artery (MCA) in rats using an injectable O-15-O-2 we developed. A decrease in CBF (left: 0.67 +/- 0.22 mL/min/g, right: 0.44 +/- 0.17 mL/min/g, P < 0.05) and compensatory increase in the oxygen extraction fraction (OEF) (left: 0.42 +/- 0.13, right: 0.50 +/- 0.19, P < 0.05) were observed at 1-h after occlusion. In contrast, a marked decrease in CBF and the cerebral metabolic rate for oxygen and a collapse of the compensatory OEF mechanism were found at 24 h after occlusion. Injectable O-15-O-2 could be used to reliably estimate oxygen metabolism in an infarction rat model with positron emission tomography.
• Myocardial flow reserve is influenced by both coronary artery stenosis severity and coronary risk factors in patients with suspected coronary artery disease

  Takahiro Tsukamoto, Koichi Morita, Masanao Naya, Chietsugu Katoh, Masayuki Inubushi, Yuji Kuge, Hiroyuki Tsutsui, Nagara Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 33 (10) 1150 - 1156 1619-7070 2006/10 [Refereed][Not invited]
   

  Purpose: Myocardial flow reserve (MFR) measurement has an important role in assessing the functional severity of coronary artery stenosis. However, a discrepancy between the anatomical severity of coronary artery stenosis and MFR is often observed. Such a discrepancy may be explained by coronary risk factors. In this study, we aimed to investigate the influence of coronary artery stenosis severity and risk factors on MFR. Methods: Seventy-four patients suspected to have coronary artery disease and seven age-matched healthy volunteers were enrolled. Myocardial blood flow (MBF) and MFR were measured using O-15-labelled water PET. Regional MFR was calculated in regions with significant coronary artery stenosis (stenotic regions) and in regions without significant stenosis (remote regions). The contributions of coronary artery stenosis severity and coronary risk factors were assessed using univariate and multivariate analyses. Results: In stenotic regions, MFR correlated inversely with coronary artery stenosis severity (r=-0.50, p < 0.01). Univariate analysis did not show any significant difference in MFR between the patients with and the patients without each risk factor. In remote regions, however, MFR was significantly decreased in the diabetes and smoking groups (each p < 0.05). By multivariate analysis, diabetes and smoking were independent predictors of MFR (each p < 0.05). In the group with more than one risk factor, MFR was significantly lower (2.78 +/- 0.79) than in the other group (3.40 +/- 1.22, p < 0.05). Conclusion: MFR is influenced not only by coronary stenosis severity but also by coronary risk factors. In particular, the influence of risk factors should be considered in regions without severe coronary stenosis.
• A new convenient method for the synthesis of [2-C-11]thymine utilizing [C-11]phosgene

  Kazue Ohkura, Ken-ichi Nishijima, Kimihito Sanoki, Yuji Kuge, Nagara Tamaki, Koh-ichi Seki

  TETRAHEDRON LETTERS 47 (30) 5321 - 5323 0040-4039 2006/07 [Refereed][Not invited]
   

  beta-(N-Benzoylamino)methacrylamide, a key intermediate for the preparation of [2-C-11]thymine, was synthesized in three steps from ethyl alpha-formylpropionate and NH3. Reaction of the alkali metal salts of beta-(N-benzoylamino)methacrylamide with [C-11]phosgene gave [2-C-11]thymine. The yield of [2-11C]thymine was 362 +/- 53 MBq at EOS (n = 3) (18 MeV proton beam; 10 mu A, 10 min). The total synthesis was accomplished in just 16 min from the end of bombardment. (c) 2006 Elsevier Ltd. All rights reserved.
• Loss of neuronal integrity: a cause of hypometabolism in patients with traumatic brain injury without MRI abnormality in the chronic stage

  T Shiga, K Ikoma, C Katoh, H Isoyama, T Matsuyama, Y Kuge, H Kageyama, T Kohno, S Terae, N Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 33 (7) 817 - 822 1619-7070 2006/07 [Refereed][Not invited]
   

  Purpose: Traumatic brain injury (TBI) causes brain dysfunction in many patients. However, some patients have severe brain dysfunction but display no abnormalities on magnetic resonance imaging (MRI). There have been some reports of hypometabolism even in such patients. The purpose of this study was to investigate the relationship between metabolic abnormality and loss of neuronal integrity in TBI patients with some symptoms but without MRI abnormalities. Methods: The study population comprised ten patients with TBI and ten normal volunteers. All of the patients were examined at least 1 year after the injury. O-15-labelled gas PET and [C-11]flumazenil (FMZ) positron emission tomography (PET) were carried out. The cerebral metabolic rate of oxygen (CMRO2) and binding potential (BP) images of FMZ were calculated. Axial T2WI, T2*WI and FLAIR images were obtained. Coronal images were added in some cases. Results: All of the patients had normal MRI findings, and all showed areas with abnormally low CMRO2. Low uptake on BP images was observed in six patients (60%). No lesions that showed low uptake on BP images were without low CMRO2. On the other hand, there were 14 lesions with low CMRO2 but without BP abnormalities. Conclusion: These results indicate that there are metabolic abnormalities in TBI patients with some symptoms after brain injury but without abnormalities on MRI. Some of the hypometabolic lesions showed low BP, indicating a loss of neuronal integrity. Thus, FMZ PET may have potential to distinguish hypometabolism caused by neuronal loss from that caused by other factors.
• Synthesis and evaluation of radioiodinated (S,S)-2-(alpha-(2-iodophenoxy)benzyl)morpholine for imaging brain norepinephrine transporter

  Naoki Kanegawa, Yasushi Kiyono, Hiroyuki Kimura, Taku Sugita, Satomi Kajiyama, Hidekazu Kawashima, Masashi Ueda, Yuji Kuge, Hideo Saji

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 33 (6) 639 - 647 1619-7070 2006/06 [Refereed][Not invited]
   

  Purpose: Abnormality of the brain norepinephrine transporter ( NET) has been reported in several psychiatric and neuronal disorders. Since NET is an important target for the diagnosis of these diseases, the development of radiopharmaceuticals for imaging of brain NET has been eagerly awaited. In this study, we synthesized (S, S)-2-(alpha-(2-iodophenoxy) benzyl) morpholine [( S, S)-IPBM], a derivative of reboxetine iodinated at position 2 of the phenoxy ring, and evaluated its potential as a radiopharmaceutical for imaging brain NET using SPECT. Methods: (S, S)-I-123/125-IPBM was synthesized in a halogen exchange reaction. The affinity and selectivity of ( S, S)IPBM for NET was measured by assaying the displacement of H-3-nisoxetine and (S, S)-I-125-IPBM from the binding site in rat brain membrane, respectively. The biodistribution of (S, S)-I-125-IPBM was also determined in rats. Furthermore, SPECT studies with (S, S)-I-123-IPBM were carried out in the common marmoset. Results: (S, S)-I-125-IPBM was prepared with high radiochemical yields (65%) and high radiochemical purity (> 98%). ( S, S)-IPBM showed high affinity and selectivity for NET in the binding assay experiments. In biodistribution experiments, (S, S)-I-125-IPBM showed rapid uptake in the brain, and the regional cerebral distribution was consistent with the density of NET. The administration of nisoxetine, a selective NET-binding agent, decreased the accumulation of (S, S)-I-125-IPBM in the brain, but the administration of selective serotonin transporter and dopamine transporter binding agents caused no significant changes in the accumulation. Moreover, (S, S)-I-123-IPBM allowed brain NET imaging in the common marmoset with SPECT. Conclusion: These results suggest that (S, S)-I-123-IPBM is a potential SPECT radiopharmaceutical for imaging brain NET.
• Change of central cholinergic receptors following lesions of nucleus basalis magnocellularis in rats: search for an imaging index suitable for the early detection of Alzheimer's disease

  M Ogawa, Y Iida, M Nakagawa, Y Kuge, H Kawashima, A Tominaga, M Ueda, Y Magata, H Saji

  NUCLEAR MEDICINE AND BIOLOGY 33 (2) 249 - 254 0969-8051 2006/02 [Refereed][Not invited]
   

  Cholinergic system in the central nervous system is involved in the memory function. Thus, because the dysfunction of cholinerglic system that project to the cerebral cortex from nucleus basalis of Meynert (nbM) Would be implicated in the memory function deficits in Alzheimer's disease (AD), evaluating cholinergic function may be useful for the early detection of AD. In this study, because the nucleus basalis magnocellularis (NBM) in rats is equivalent to nbM ill human, We investigated the change in cholinergic receptors in the frontal cortex of rats With unilateral lesion to the NBM to find an appropriate index for the early detection of AD using techniques Of nuclear medicine. The right NBM was injected with ibotenic acid. [F-18]FDG-PET images were obtained 3 days later. Some rats were sacrificed at 1 week, whereas others were subjected to a second [F-18]FDG-PET at 4 weeks then sacrificed for membrane preparation. The prepared membranes were Subjected to radioreceptor assays to Measure the density of nicotinic and muscarinic acetylcholine receptors. Glucose metabolism had decreased oil the damaged side compared to the control side at 3 clays, but at 4 weeks, there was no difference between the sides. Nicotinic acetylcholine receptors had significantly decreased in density compared to the control side at both I and 4 weeks. However, muscarinic receptors were not affected. These results suggested that neuronal dysfunction in AD could be diagnosed at all early stage by imaging nicotinic acetylcholine receptors. (c) 2006 Elsevier Inc. All rights reserved.
• Synthesis and evaluation of radioiodinated cyclooxygenase-2 inhibitors as potential SPECT tracers for cyclooxygenase-2 expression

  Y Kuge, Y Katada, S Shimonaka, T Temma, H Kimura, Y Kiyono, C Yokota, K Minematsu, K Seki, N Tamaki, K Ohkura, H Saji

  NUCLEAR MEDICINE AND BIOLOGY 33 (1) 21 - 27 0969-8051 2006/01 [Refereed][Not invited]
   

  Although several COX-2 inhibitors have recently been radiolabeled, their potential for imaging COX-2 expression remains unclear. In particular, the sulfonamide moiety of COX-2 inhibitors may cause slow blood clearance of the radiotracer, due to its affinity for carbonic anhydrase (CA) in erythrocytes. Thus, we designed a methyl sulfone-type analogue, 5-(4-iodophenyl)-1-[4-(methylsulfonyl)phenyl]-3-trifluoromethyl-1H-pyrazole (IMTP). In this study, the potential of radioiodinated IMTP was assessed in comparison with a I-125-labeled celecoxib analogue with a sulfonamide moiety (I-125-IATP). Methods: The COX inhibitory potency was assessed by measuring COX-catalyzed oxidation by hydrogen peroxide. The biodistribution of I-125-IMTP and I-125-IATP was determined by the ex vivo tissue counting method in rats. Distribution of the labeled compounds to rat blood cells was measured. Results: The COX-2 inhibitory potency of IMTP (IC50=5.16 mu M) and IATP (IC50=8.20 mu M) was higher than that of meloxicam (IC50-29.0 mu M) and comparable to that of SC-58125 (IC50=1.36 mu M). The IC50 ratios (COX-1/COX-2) indicated the high isoform selectivity of IMTP and IATP for COX-2. Significant levels of I-125-IMTP and 125 MATP were observed in the kidneys and the brain (organs known to express COX-2). The blood clearance of I-125-IMTP was much faster than that of I-125-IATP. Distribution of (125) I-IATP to blood cells (88.0%) was markedly higher than that of I-125-IMTP (18.1%), which was decreased by CA inhibitors. Conclusions: Our results showed a high inhibitory potency and selectivity of IMTP for COX-2. The substitution of a sulfonamide moiety to a methyl sulfone moiety effectively improved the blood clearance of the compound, indicating the loss of the cross reactivity with CA in I-125-IMTP. I-123-IMTP may be a potential SPECT radiopharmaceutical for COX-2 expression. (c) 2006 Elsevier Inc. All rights reserved.
• Evaluating performance of a pixel array semiconductor SPECT system for small animal imaging

  N Kubo, S Zhao, Y Fujiki, A Kinda, N Motomura, C Katoh, T Shiga, H Kawashima, Y Kuge, N Tamaki

  ANNALS OF NUCLEAR MEDICINE 19 (7) 633 - 639 0914-7187 2005/10 [Refereed][Not invited]
   

  Objectives: Small animal imaging has recently been focused on basic nuclear medicine. We have designed and built a small animal SPECT imaging system using a semiconductor camera and a newly designed collimator. We assess the performance of this system for small object imaging. Methods: We employed an MGC1500 (Acrorad Co.) camera including a CdTe semiconductor. The pixel size was 1.4 mm/pixel. We designed and produced a parallel-hole collimator with 20-mm hole length. Our SPECT system consisted of a semiconductor camera with the subject holder set on an electric rotating stage controlled by a computer. We compared this system with a conventional small animal SPECT system comprising a SPECT-2000H scanner with four Anger type cameras and pinhole collimators. The count rate linearity for estimation of the scatter was evaluated for a pie-chart phantom containing different concentrations of Tc-99m. We measured the FWHM of the Tc-99m SPECT line source along with scatter. The system volume sensitivity was examined using a flood source phantom which was 35 mm long with a 32-mm inside diameter. Additionally, an in vivo myocardial perfusion SPECT study was performed with a rat. Results: With regards to energy resolution, the semiconductor camera (5.6%) was superior to the conventional Anger type camera (9.8%). In the count rate linearity evaluation, the regression lines of the SPECT values were y = 0.019x + 0.031 (r(2) = 0.999) for our system and y = 0.018x + 0.060 (r(2) = 0.997) for the conventional system. Thus, the scatter count using the semiconductor camera was less than that using the conventional camera. FWHMs of our system and the conventional system were 2.9 +/- 0.1 and 2.0 +/- 0.1 mm, respectively. Moreover, the system volume sensitivity of our system [0.51 kcps/(MBq/ml)/cm] was superior to that of the conventional system [0.44 kcps/(MBq/ml)/cm]. Our system provided clear images of the rat myocardium, sufficient for practical use in small animal imaging. Conclusions: Our SPECT system, utilizing a semiconductor camera, permits high quantitative analysis by virtue of its low scatter radiation and high sensitivity. Therefore, this system may contribute to molecular imaging of small animals and basic medical research.
• Quantitative analysis of myocardial glucose utilization in patients with left ventricular dysfunction by means of F-18-FDG dynamic positron tomography and three-compartment analysis

  K Morita, C Katoh, K Yoshinaga, K Noriyasu, M Mabuchi, T Tsukamoto, H Kageyama, T Shiga, Y Kuge, N Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 32 (7) 806 - 812 1619-7070 2005/07 [Refereed][Not invited]
   

  Purpose: Myocardial glucose utilization (MGU) is altered in various heart diseases. The aim of this study was to quantitatively assess regional myocardial glucose utilization in patients with left ventricular (LV) dysfunction by dynamic F-18-fluorodeoxyglucose positron emission tomography (FDG PET). Methods: A total of 18 subjects were studied, including ten with LV dysfunction ( seven with idiopathic dilated cardiomyopathy and three with aortic regurgitation; NYHA II in 8 and III in 2) and eight healthy normal volunteers. Patients with diabetes mellitus were excluded. A dynamic PET study was performed for 40 min following the injection of 370 MBq of FDG after 50-g glucose loading. On the basis of a three-compartment model, MGU, K-1, k(2), and k(3) were computed on a pixel by pixel basis to generate LV myocardial parametric maps. FDG standardized uptake value (SUV) was also calculated using static images obtained 40 min after FDG injection. These metabolic values were compared with myocardial flow distribution (% Flow), LVEF, LV volumes, and LV wall thickening (WT) determined by gated myocardial single-photon emission computed tomography using QGS software in eight myocardial segments. Results: MGU correlated positively with LV volumes and negatively with LVEF. K1 was significantly higher in the segments of the patients than in those of the normal volunteers ( 0.082 +/- 0.055 vs 0.041 +/- 0.017 ml min(-1) g(-1), p< 0.05), although there was no difference in MGU between the groups. On the other hand, SUV, k(2), and k(3) did not differ significantly between the groups. Among the patients, the K-1 values were significantly higher in the areas with impaired WT (% WT< 17%) (0.109 +/- 0.063 vs 0.069 +/- 0.062 ml min(-1) g(-1), p< 0.05) and in the areas with flow reduction (% Flow< 71%) (0.112 +/- 0.076 vs 0.071 +/- 0.046 ml min(-1) g(-1), p< 0.05). Conclusion: These results indicate that glucose utilization was preserved in the patients with LV dysfunction, mainly due to an increase in glucose transport, particularly in the regions with severely impaired LV function. Thus, the quantitative assessment of myocardial glucose utilization by FDG dynamic PET may provide useful information for assessing the regional myocardial metabolic status in patients with LV dysfunction.
• Bilateral induction of the S-100A9 gene in response to spreading depression is modulated by the cyclooxygenase-2 activity

  C Yokota, Y Kuge, H Inoue, N Tamaki, K Minematsu

  JOURNAL OF THE NEUROLOGICAL SCIENCES 234 (1-2) 11 - 16 0022-510X 2005/07 [Refereed][Not invited]
   

  Cyclooxygenase-2 (COX-2) was reported to be induced in the infarcted human brain. Spreading depression (SD) is thought to play a role in this induction. In this study, we correlated the expression of SD-associated genes with COX-2 production in brains after SD. Rats were divided into 3 groups: rats that did not undergo SD (group I saline controls, n=7), rats that underwent unilateral SD as a result of KCl application (group II, n=9), and rats that were pretreated with the selective COX-2 inhibitor, JTE-522 3 h before the induction of SD (group III, n=7). The expression of the SD-associated genes, S-100A9, and mitogen-activated proteinkinase phosphatase (cpg21) was analyzed 2 h later using a cDNA array. In group II, COX-2 and cpg21 mRNA expression, as determined by RT-PCR, were significantly upregulated in the hemisphere undergoing SD. While the expression of S-100A9 mRNA was bilaterally upregulated in these animals, this expression was significantly reduced in group III, and was accompanied by reduced bilateral production of PGE(2). Thus, the bilateral induction of expression of the S-100A9 gene in response to SD was associated with COX-2 activation. (c) 2005 Elsevier B.V. All rights reserved.
• Aggravation of hemorrhagic transformation by early intraarterial infusion of low-dose vascular endothelial growth factor after transient focal cerebral ischemia in rats

  T Abumiya, C Yokota, Y Kuge, K Minematsu

  BRAIN RESEARCH 1049 (1) 95 - 103 0006-8993 2005/07 [Refereed][Not invited]
   

  Vascular endothelial growth factor (VEGF) is a unique growth factor associated with angiogenesis, vascular permeability, and neuroprotection. The aim of this study was to observe the effects of early intraarterial infusion of low-dose VEGF on ischemia/reperfusion injury after transient focal cerebral ischemia in rats. Male Sprague-Dawley rats were subjected to 2 h of focal ischemia by middle cerebral artery occlusion. After the 2 It ischemia, the rats were infused with 0.3 mu g/kg of VEGF (n = 15), or the vehicle as a control (n = 15), via the reperfused internal carotid artery. The brains were collected after a I h, 6 It, or 72 h reperfused period. Severity of ischemic cellular injury, serum extravasation, hemorrhagic transformation, and matrix metalloproteinase (MMP)-2 and -9 expressions were compared between the VEGF-treated and control groups. No significant difference in the extent of ischemic cellular injury and serum extravasation was observed between the two groups. However, vessel numbers with hemorrhagic transformation were significantly greater in the VEGF-treated group than in the control group after the 72 h reperfusion (9.4 +/- 1.6 versus 2.6 +/- 1.5; P = 0.028). The severity of hemorrhagic transformation was not correlated with the extent of ischemic cellular injury or serum extravasation. MMP-2 and -9 expressions were not enhanced in the VEGF-treated group compared with the control group. These results suggest that exogenous VEGF administered intravascularly at a very early point in reperfusion aggravates hemorrhagic transformation. The aggravated hemorrhagic transformation does not seem to depend on the enlargement of ischemic cellular injury, serum extravasation, or overexpressions of MMP-2 and -9. (c) 2005 Elsevier B.V. All rights reserved.
• Enhanced apoptotic reaction correlates with suppressed tumor glucose utilization after cytotoxic chemotherapy: Use of Tc-99m-annexin V, F-18-FDG, and histologic evaluation

  T Takei, Y Kuge, S Zhao, M Sato, HW Strauss, FG Blankenberg, JF Tait, N Tamaki

  JOURNAL OF NUCLEAR MEDICINE 46 (5) 794 - 799 0161-5505 2005/05 [Refereed][Not invited]
   

  Cancer chemotherapy enhances the apoptosis, whereas apoptosis is a suicidal mechanism requiring energy. We determined the relationship between apoptosis and glucose utilization during cancer chemotherapy using Tc-99m-annexin V (Tc-99m-annexin A5) and F-18-FDG and compared their uptake with histologic findings in a rat tumor model. Methods: Allogenic hepatoma cells (KDH-8) were inoculated into the left calf muscle of male Wistar rats (WKA). Eleven days after the inoculation, the rats were randomly divided into 3 groups: The first group (n = 7) received a single dose of gemcitabine (90 mg/kg, intravenously), the second group (n = 8) received cyclophosphamide (150 mg/kg, intraperitoneally), and the third group (n = 7) was untreated and served as the control group. We injected Tc-99m-annexin V 48 h after the chemotherapy and then injected F-18-FDG to all rats 1 h before sacrifice. Six hours after 99mTc-annexin V injection, the rats were sacrificed and the organs, including the tumor, were removed and radioactivity was counted. The radioactivities of F-18 and Tc-99m in the organs were determined using normalization by tissue weight. Histologic evaluation by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) method and the immunostaining of glucose transporter-1 (GLUT-1) were also performed to obtain the indices of apoptosis and glucose utilization, respectively. The rate of positively stained cells was calculated and analyzed statistically. Results: After chemotherapy using gemcitabine and cyclophosphamide, the Tc-99m-annexin V uptake (percentage injected dose per gram x kg [(%ID/g) x kg]; mean &PLUSMN; SD) in tumor increased significantly (0.062 &PLUSMN; 0.012 (%ID/g) X kg in the gemcitabine-treated group and 0.050 &PLUSMN; 0.012 (%ID/g) X kg in the cyclophosphamide group vs. 0.031 &PLUSMN; 0.005 (%ID/g) X kg in the control group; P < 0.01). In contrast, the 18F-FDG in tumor decreased significantly (0.483 &PLUSMN; 0.118 (%ID/g) x kg in the gemcitabine group and 0.583 &PLUSMN; 0.142 (%ID/g) x kg in the cyclophosphamide group) compared with that in the control group (0.743 &PLUSMN; 0.084 (%ID/g) X kg; P < 0.01). in addition, F-18-FDG uptake in tumor negatively correlated with Tc-99m-annexin V uptake (r = -0.75; P < 0.01). In the gemcitabine and cyclophosphamide groups, the rate of TUNEL positively stained cells was significantly higher than that in the control group (10.2% &PLUSMN; 1.7% and 8.0% &PLUSMN; 1.5% vs. 5.2% &PLUSMN; 1.5%; P < 0.01), whereas the GLUT-1 expression level showed no definite changes in histologic analyses. Conclusion: These data indicate that an enhanced apoptotic reaction correlated with suppressed tumor glucose utilization after cytotoxic chemotherapy as determined using radiotracers and histologic evaluation. The increase in Tc-99m-annexin V and the decrease in F-18-FDG in tumor can be useful markers for predicting therapeutic outcomes and for prognosis at the early stage of chemotherapy.
• Biologic correlates of intratumoral heterogeneity in F-18-FDG distribution with regional expression of glucose transporters and hexokinase-II in experimental tumor

  SJ Zhao, Y Kuge, T Mochizuki, T Takahashi, K Nakada, M Sato, T Takei, N Tamaki

  JOURNAL OF NUCLEAR MEDICINE 46 (4) 675 - 682 0161-5505 2005/04 [Refereed][Not invited]
   

  The biologic mechanisms involved in the intratumoral heterogeneous distribution of F-18-FDG have not been fully investigated. To clarify factors inducing heterogeneous F-18-FDG distribution, we determined the intratumoral distribution of F-18-FDG by autoradlography (ARG) and compared it with the regional expression levels of glucose transporters Glut-1 and Glut-3 and hexokinase-II (HK-II) in a rat model of malignant tumor. Methods: Rats were inoculated with allogenic hepatoma cells (KDH-8) into the left calf muscle (n = 7). Tumor tissues were excised 1 h after the intravenous injection of F-18-FDG and sectioned to obtain 2 adjacent slices for ARG and histochemical studies. The regions of interest (ROIs) were placed on ARG images to cover mainly the central (CT) and peripheral (PT) regions of viable tumor tissues and necrotic/apoptotic (NA) regions. The radioactivity in each ROI was analyzed quantitatively using a computerized imaging analysis system. The expression levels of Glut-1, Glut-3, and HK-II were determined by immunostaining and semiquantitative evaluation. The hypoxia-inducible factor 1 alpha (HIF-1 alpha) was also immunostained. Results: ARG images showed that intratumoral F-18-FDG distribution was heterogeneous. The accumulation of F-18-FDG in the CT region was the highest, which was 1.6 and 2.3 times higher than those in the PT and NA regions, respectively (P < 0.001). The expression levels of Glut-1, Glut-3, and HK-II were markedly higher in the CT region (P < 0.001) compared with those in the PT region. The intratumoral distribution of F-18-FDG significantly correlated with the expression levels of Glut-1, Glut-3, and HK-II (r = 0.923, P < 0.001 for Glut-1; r = 0.829, P < 0.001 for Glut-3; and r = 0.764, P < 0.01 for HK-II). The positive staining of HIF-1 alpha was observed in the CT region. Conclusion: These results demonstrate that intratumoral F-18-FDG distribution corresponds well to the expression levels of Glut-1, Glut-3, and HK-II. The elevated expression levels of Glut-1, Glut-3, and HK-II, induced by hypoxia (HIF-1 alpha a), may be contributing factors to the higher F-18-FDG accumulation in the CT region.
• Time course of apoptotic tumor response after a single dose of chemotherapy: Comparison with 99mTc-annexin V uptake and histologic findings in an experimental model

  Toshiki Takei, Yuji Kuge, Songji Zhao, Masayuki Sato, H. William Strauss, Francis G. Blankenberg, Jonathan F. Tait, Nagara Tamaki

  Journal of Nuclear Medicine 45 (12) 2083 - 2087 0161-5505 2004/12/01 [Refereed][Not invited]
   

  In tumors the process of apoptosis occurs over an interval of time after chemotherapy. To determine the best timing for detecting apoptosis in vivo with 99mTc-annexin V after chemotherapy, we examined the changes in 99mTc-annexin V accumulation over time in comparison with those of caspase-3 and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) expression level after cyclophosphamide treatment in an experimental model. Methods: Hydrazinonicotinamide (HYNIC)-annexin V was labeled with 99mTc (99mTc-annexin V). Rats were inoculated with allogenic hepatoma cells (KDH-8) into the left calf muscle. Eleven days after the inoculation, the rats were randomly divided into the group receiving a single dose of cyclophosphamide (150 mg/kg intraperitoneally) and the control group. 99mTc-Annexin V (18.5 MBq [0.5 mCi] per rat) was injected intravenously in the rats 4, 12, and 20 h after the treatment and also to the control rats (n = 5 in each group). Radioactivity in tissues was determined 6 h after 99mTc-annexin V injection. Immunostaining of caspase-3 and TUNEL were performed to detect apoptosis, and the rates of positively stained cells were calculated. Results: 99mTc-Annexin V accumulation in tumors significantly increased at 20 h (0.077 ± 0.007 [%ID/g] x kg, where %ID/g = percentage injected dose per gram) but not at 4 or 12 h (0.048 ± 0.008 and 0.052 ± 0.014 [%ID/g] x kg, respectively) after cyclophosphamide treatment. 99mTc-Annexin V accumulation in tumors and the rate of apoptotic cells determined by caspase-3 immunostaining and TUNEL were significantly higher in treated rats 20 h after cyclophosphamide treatment as compared with control rats. Conclusion: The effective detection of apoptotic tumor response with 99mTc-annexin V required 20 h after cyclophosphamide treatment in an experimental model. The present results provide an important basis for determining the best timing of annexin V imaging after the start of chemotherapy in a clinical setting.
• Reduced oxidative metabolic response in dysfunctional myocardium with preserved glucose metabolism but with impaired contractile reserve

  K Yoshinaga, C Katoh, RSB Beanlands, K Noriyasu, K Komuro, S Yamada, Y Kuge, K Morita, A Kitabatake, N Tamaki

  JOURNAL OF NUCLEAR MEDICINE 45 (11) 1885 - 1891 0161-5505 2004/11 [Refereed][Not invited]
   

  The recovery of function in myocardium defined as viable by F-18-FDG PET may differ from that defined by dobutamine stress echocardiography (DSE). The aim of this study was to investigate the difference in the oxidative metabolic response between myocardial segments with preserved contractile reserve (CR) and those without CR, in segments with and without preserved glucose metabolism (GM), using C-11-acetate PET. Methods: Twenty patients with previous myocardial infarction (left ventricular ejection fraction, 37.1% +/- 16.5%) underwent dynamic C-11-acetate PET at rest and during dobutamine (7.5 mug/kg/min) infusion. GM was evaluated using 18F-FDG PET and CR was evaluated using DSE. Dysfunctional segments were divided into 3 groups: group A (n = 26) with preserved CR and GM, group B (n = 15) without CR but with preserved GM, and group C (n = 41) without CR and without preserved GM. Results: Resting oxidative metabolism (k mono = monoexponential clearance rate) was preserved in group A and group B (0.052 +/- 0.011/min vs. 0.051 +/- 0.012/min, P = not significant) but was reduced in group C (0.040 +/- 0.015/min) (P < 0.03 vs. group A and group B). The change in k mono, as a measure of the metabolic response to low-dose dobutamine, was significantly higher in group A (0.018 +/- 0.012) than that in group B (0.0075 +/- 0.0096, P < 0.03) and group C (0.0080 +/- 0.012, P < 0.005). Conclusion: Viable segments based on F-18-FDG PET have preserved resting oxidative metabolism. However, segments without CR but with preserved GM show a reduction in the oxidative metabolic response to low-dose dobutamine infusion. The decrease in CR may be related to the reduction in the metabolic response to inotropic stimulation despite preservation of tissue viability on F-18-FDG PET.
• Preparation and pharmaceutical evaluation for clinical application of high specific activity S-(-)[C-11]CGP-12177, a radioligand for beta-adrenoreceptors

  K Nishijima, Y Kuge, K Seki, K Ohkura, K Morita, K Nakada, N Tamaki

  NUCLEAR MEDICINE COMMUNICATIONS 25 (8) 845 - 849 0143-3636 2004/08 [Refereed][Not invited]
   

  Background Although S-(-)[C-11]CGP-12177 is a useful positron emission tomography (PET) ligand for beta-adrenoreceptors, the difficulty in radiolabelling the compound has prevented its extensive clinical application. Recently, we have developed a simple synthesis method for S-(-)[C-11]CGP-12177. In the present study, we attempted to prepare S-(-)[C-11]CGP-12177 with a high specific activity for intravenous injection which is feasible for the clinical evaluation of beta-adrenoreceptors. Methods The [C-11]methane produced during irradiation of a N-2-H-2 (95/5) mixture with an 18 MeV proton beam (20 muA, 30 min) was chlorinated using Cl-2 to yield [C-11]carbon tetrachloride. S-(-)[C-11]CGP-12177 was synthesized by reacting the diamino precursor with [C-11]phosgene produced by oxidizing [C-11]carbon tetrachloride on a Fe-Fe2O3 column. The product was purified by using reversed phase, high-performance liquid chromatography (RP-HPLC) and the radioactive fraction containing S-(-)[C-11]CGP-12177 was collected and evaporated to dryness. S-(-)[C-11]CGP-12177 dissolved in physiological saline was sterilized through a 0.22 mum membrane filter. The radiochemical purity and the mass of the compound were determined with RP-HPLC. The residual organic solvents were determined with GC. Tests for sterility and the presence of bacterial endotoxins were also performed. Results S-(-)[C-11]CGP-12177 for intravenous injection was prepared in 25 min after the end of bombardment with a yield of 1.5 +/- 0.2 GBq. Specific activity was found to be 385.4 +/- 133.0 GBq/mumol at the end of synthesis (EOS) (n = 3). Radiochemical purity was found to be more than 99%. Toluene was not detected in the solution. The ethanol concentration was determined to be 60.3 +/- 52.5 ppm. Tests for sterility and bacterial endotoxins showed negative results. Conclusion We successfully prepared S-(-)[C-11]CGP-12177 formulated for intravenous injection with high purity and high specific activity, which is feasible for the clinical evaluation of beta-adrenoreceptors. (C) 2004 Lippincott Williams Wilkins.
• Effect of steroids on [F-18]fluorodeoxyglucose uptake in an experimental tumour model

  S Zhao, Y Kuge, K Nakada, T Mochizuki, T Takei, F Okada, N Tamaki

  NUCLEAR MEDICINE COMMUNICATIONS 25 (7) 727 - 730 0143-3636 2004/07 [Refereed][Not invited]
   

  Background It is well known that blood glucose level affects the uptake of 2-[F-18]fluoro-2-deoxy-D-glucose (FDG) in tumours. Thus, the action of steroids on glucose metabolism may alter blood glucose levels and may affect FDG uptake in tumours in patients treated with steroids. To clarify this point, we determined the effects of steroids on FDG uptake in tumours in a rat model of a malignant tumour. Methods Rats were inoculated with allogenic hepatoma cells (KDH-8) into the left calf muscle. They were fasted overnight and divided into three groups (n=5 in each group): (1) dexamethasone (DEX) pretreated (0.8 mg(.)kg(-1) body weight, i.m. injection 4 h before FDG i.v. injection); (2) prednisolone (PRE) pretreated (8 mg(.)kg(-1) body weight, i.m. injection 20 h before FDG i.v. injection); and (3) control (untreated) groups. Radioactivity in tissues was determined 1 h after i.v. injection of FDG. FDG uptake in the tumour was expressed as the percentage of injected dose per gram of tissue after normalization to animal's weight (%ID/g tissue/kg body weight). Results DEX and PRE pretreatments significantly increased the blood glucose levels to 128% and 145% of the control value. The levels of FDG uptake in the tumour were not significantly affected by DEX and PRE pretreatment (90% and 87% of the control value, respectively) (P=NS). Conclusions These results demonstrate that FDG uptake in the tumour was not affected by pretreatment with steroids, in spite of a slight elevation in blood glucose level. (C) 2004 Lippincott Williams Wilkins.
• Use of a standardized uptake value for parametric in vivo imaging of benzodiazepine receptor distribution on [C-11]flumazenil brain PET

  M Tsukamoto, C Katoh, T Shiga, T Kaji, Y Kuge, K Nakada, N Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 31 (6) 846 - 851 1619-7070 2004/06 [Refereed][Not invited]
   

  To simplify the acquisition protocol of carbon-11 labeled flumazenil (FMZ) positron emission tomography (PET) for distribution volume (DV) images, we attempted to obtain standardized uptake value (SUV) images compatible with DV images, and assessed the applicability of this method in patients with unilateral cerebrovascular diseases (CVD). [C-11]FMZ PET was performed in ten normal subjects. A DV image and ten sequential 5-min SUV images were generated for each subject. We investigated the correlation coefficient (r) and standard estimation of error (SEE) between the latter ten static images and the DV image using the pixel-by-pixel method, thereby determining the optimum acquisition phase. The same FMZ PET procedure was performed in 15 patients with unilateral CVD. Twenty regions of interest (ROIs) were positioned both in lesioned areas and in symmetrical regions. DV and SUV in the optimum phase for each ROI were calculated to compare the lesion-to-normal (L/N) ratio of DV and that of SUV. The highest r and a low SEE (r=0.957, SEE=633) were observed from 30 to 35 min after tracer administration in the study of normal subjects. A high r (0.945) and a low SEE (0.0438) between the DV L/N ratio and the SUV L/N ratio were obtained in the study of patients. Our study suggests that SUV images acquired from 30 to 35 min after FMZ administration are a suitable alternative to DV images not only in normal subjects but also in patients with unilateral CVD. This simple method seems to be valuable for the identification of altered neuronal activity in patients with CVD.
• Temporal and topographic profiles of cyclooxygenase-2 expression during 24 h of focal brain ischemia in rats

  C Yokota, T Kaji, Y Kuge, H Inoue, N Tamaki, K Minematsu

  NEUROSCIENCE LETTERS 357 (3) 219 - 222 0304-3940 2004/03 [Refereed][Not invited]
   

  Substantial increases in cyclooxygenase-2 (COX-2) mRNA and protein levels were demonstrated in the peri-infarct and focal ischemic areas after 3-24 and 12-24 h, respectively, in rats. In the ischemic core, significant increases in COX-2 mRNA followed 6 h of ischemia, though the peak level was about one-third of that in the peri-infarct area. Increases in COX-2 protein in the ischemic core were not observed during ischemic periods. Diffuse, neuronal COX-2 staining was found in peri-infarct areas as well as in discrete, immunoreactive neurons in the ischemic core. Robust increases in prostaglandin E-2 levels in the peri-infarct area were demonstrated following 24 h of ischemia. Prostaglandin production as well as COX-2 expression in ischemic tissues depended on the degree and duration of the reduction in cerebral blood flow. (C) 2003 Elsevier Ireland Ltd. All rights reserved.
• Feasibility of Tc-99m-annexin V for repetitive detection of apoptotic tumor response to chemotherapy: An experimental study using a rat tumor model

  Y Kuge, M Sato, SJ Zhao, T Takei, K Nakada, K Seki, HW Strauss, FG Blankenberg, JF Tait, N Tamaki

  JOURNAL OF NUCLEAR MEDICINE 45 (2) 309 - 312 0161-5505 2004/02 [Refereed][Not invited]
   

  Annexin V (annexin A5), a human protein with a high affinity for phosphatidylserine, labeled with Tc-99m can detect apoptosis in vivo. In the repetitive detection of apoptosis with Tc-99m-annexin V, however, the specific binding of annexin V to phosphatidyl-serine might affect the subsequent detection of apoptosis with this compound. To determine whether there is interference with repetitive doses of annexin V, we evaluated the effects of previous administration of cold annexin V on accumulation of 99mTc-annexin V in tumors in an experimental tumor model. Methods: Rats bearing hepatoma received cyclophosphamide (150 mg/kg, intraperitoneally) 11 d after the tumor inoculation. Cold annexin V (20 mug/kg, intravenously) was administered 24 h before or after the cyclophosphamide treatment (n = 7/group). Tc-99m-Annexin V was injected intravenously (radioactive dose, 5-23 MBq/kg; mass dose, 20 mug/kg), and radioactivity in tissues was determined 6 h later. Results: Accumulation of Tc-99m-annexin V in tumors was not significantly affected by previous treatment with cold annexin V before or after chemotherapy. Conclusion: These results demonstrate the feasibility of Tc-99m-annexin V imaging for repetitive detection of apoptosis, which is highly required in the clinical setting.
• Characterisation of [123I]iomazenil distribution in a rat model of focal cerebral ischaemia in relation to histopathological findings

  Tomohito Kaji, Yuji Kuge, Chiaki Yokota, Masafumi Tagaya, Hiroyasu Inoue, Tohru Shiga, Kazuo Minematsu, Nagara Tamaki

  European Journal of Nuclear Medicine and Molecular Imaging 31 (1) 64 - 70 1619-7070 2004/01 [Refereed][Not invited]
   

  Iodine-123 labelled iomazenil ([123I]IMZ) has been reported to be a useful marker of neuronal viability. The brain distribution of [ 123I]IMZ, however, has not been correlated with the pathophysiological response in detail after an ischaemic insult. To characterise [123I]IMZ as a marker of neuronal viability, we compared its brain distribution with cyclooxygenase-2 (COX-2) expression, DNA fragmentation and cellular integrity. [123I]IMZ and [ 125I]IMP were injected into rats with focal cerebral ischaemia for the purpose of dual-tracer autoradiography. COX-2 and microtubule-associated protein-2 (MAP-2, a marker of cellular integrity) were immunostained. In situ DNA polymerase-I-dependent dUTP incorporation into damaged DNA was used as an indicator of DNA fragmentation. Lesion to normal ratios (LNRs) for [ 123I]IMP and [125I]IMZ were calculated. [ 123I]IMZ accumulation was preserved in several regions with impaired [123I]IMP accumulation. COX-2 expression was occasionally observed, whereas neither DNA fragmentation nor MAP-2 denaturation was detected in these regions. DNA fragmentation and impaired MAP-2 immunostaining were observed only in the regions with reduced LNRs for both tracers. The LNR for [ 123I]IMZ was significantly lower in regions with impaired MAP-2 immunostaining (0.120±0.152, P< 0.0001), in regions positive for dUTP incorporation (0.488±0.166, P< 0.0001) and in regions positive for COX-2 expression (0.626±0.186, P< 0.001) than in histologically normal regions (0.784±0.213). Thus, neuronal DNA is still intact and cellular integrity is maintained in the ischaemic regions with preserved [ 123I]IMZ accumulation. The impairment of [123I]IMZ accumulation precedes DNA fragmentation and denaturation of cellular integrity. These results provide the molecular basis of [123I]IMZ distribution.
• Facile synthesis of 4a-fluoro-5,10-ethenobenzo[f]quinazolines through 1,4-photocycloaddition of 5-fluoro-1,3-dimethyluracil with substituted naphthalenes

  K Ohkura, T Sugaoi, T Ishihara, K Aizawa, K Nishijima, Y Kuge, K Seki

  HETEROCYCLES 61 377 - + 0385-5414 2003/12 [Refereed][Not invited]
   

  UV-irradiation of 6-chloro-1,3-dimethyluracil with naphthalenes underwent 1,2-cycloaddition to give naphthocyclobutapyrimidines consisting of a cyclobutene ring, The same reaction of an aprotic solution of 5-fluoro-1,3-dimethyluracil and naphthalenes bearing various substituents underwent 1,4-cycloaddition mode-selectively to give the corresponding ethenobenzoquinazoline derivatives with H and F atoms remaining intact on the newly constructed barrelene moiety. In protic solvents, the reaction preferentially proceeded by way of a substitution reaction to afford 5-(1-naphthyl)uracil.
• Serial changes in BMIPP uptake in relation to thallium uptake in the rat myocardium after ischaemia

  K Noriyasu, M Mabuchi, Y Kuge, K Morita, T Tsukamoto, T Kohya, A Kitabatake, N Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 30 (12) 1644 - 1650 1619-7070 2003/12 [Refereed][Not invited]
   

  Several clinical studies have shown that iodine-123 labelled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) uptake is often lower than the uptake of perfusion tracers in patients with ischaemic heart disease. However, BMIPP accumulation may not decrease during the acute phase of a stunned myocardium in patients with acute coronary syndrome. We evaluated serial changes in BMIPP and perfusion tracer uptake in the myocardium after ischaemia. We performed a 20-min left coronary artery occlusion followed by reperfusion in male Wister rats. One hour after the reperfusion, echocardiography was performed. Intravenous injection of iodine-125 labelled BMIPP and thallium-201 was performed 1 day (acute group) and 5 days (subacute group) after the operation. To determine the myocardial distribution of I-125-BMIPP and Tl-201, dual-tracer autoradiography was conducted. We identified regions of interest in the anterolateral wall as an area at risk and in the inferoseptum as a remote control area. The anterolateral wall/inferosepturn ratio (A/I ratio) was calculated to compare the distributions of I-125-BMIPP and Tl-201. Coronary occlusion induced hypokinesia in the anterolateral region 1 h after the reperfusion. The A/I ratio of I-125-BMIPP was significantly higher than that of Tl-201 in the acute group (1.01+/-0.15 vs 0.80+/-0.23, P<0.001). On the other hand, there was no significant difference between the A/I ratios of I-125-BMIPP and Tl-201 in the subacute group (0.88+/-0.18 vs 0.85+/-0.18). Two rats showed a Significantly lower A/I ratio of I-125-BMIPP than Tl-201 in the subacute phase. These data suggest that BMIPP uptake is preserved despite a decrease in perfusion in the acute phase after ischaemia. In the subacute phase, on the other hand, BMIPP uptake is similar to or even lower than thallium uptake. Since BMIPP uptake may change with time after ischaemia, careful interpretation of BMIPP uptake after ischaemia is required in a clinical setting.
• Characteristic brain distribution of 1-C-14-octanoate in a rat model of focal cerebral ischemia in comparison with those of I-123-IMP and I-123-iomazenil

  Y Kuge, K Hikosaka, K Seki, K Ohkura, K Nishijima, T Kaji, S Ueno, E Tsukamoto, N Tamaki

  JOURNAL OF NUCLEAR MEDICINE 44 (7) 1168 - 1175 0161-5505 2003/07 [Refereed][Not invited]
   

  1-C-11-Octanoate is a potential tracer for studying astroglial function in PET. To evaluate the usefulness of 1-C-11-octanoate for studying ischemic stroke, we investigated the brain distribution of 1-C-14-octanoate and compared it with N-isopropyl-p-I-123-iodoamphetamine (I-123-IMP) distribution (cerebral blood flow), I-123-iomazenil (I-123-IMZ) distribution (neuronal viability based on I-123-IMZ binding to benzodiazepine receptors); and hematoxylin-eosin stain (morphologic changes) in a rat model of focal cerebral ischemia. Methods: The right middle cerebral artery of each rat was occluded intraluminally. The brain distribution of 1-C-14-octanoate and I-123-IMP (or I-123-IMZ) was determined 4 and 24 h after the insult using a dual-tracer autoradiographic technique (n = 4-7 in each group). Coronal brain sections adjacent to those used for autoradiography were stained with hematoxylin and eosin. Regions of interest (ROIs) were determined,for 3 coronal slices, and asymmetry indices (AIs, lesion/normal hemisphere) of the tracer uptake were calculated. ROIs on the hemisphere with the lesion were classified into 4 groups: In region A, widespread necrotic cells were observed; in region B, necrotic cells were occasionally observed; in region C1, no morphologic changes were observed and the AIs for I-123-IMP (or I-123-IMZ) were less than or equal to0.8; and in region C2, no morphologic changes were observed and the AIs for I-123-IMP (or I-123-IMZ) were >0.8. Results: 1-C-14-Octanoate uptake decreased in the regions where morphologic changes were observed (regions A and B) but was relatively preserved in the surrounding region without morphologic changes despite reduced I-123-IMP and I-123-IMZ uptake (region C1). In the region without morphologic changes (region C1), AIs for 1-(14C)-octanoate were significantly higher than those for I-123-IMP (4 h, 0.73 +/- 0.23 for 1-C-14-octanoate and 0.37 +/- 0.20 for I-123-IMP, P < 0.0001; 24 h, 0.84 +/- 0.11 for 1-C-14-octanoate and 0.44 +/- 0.15 for I-123-IMP, P < 0.0001) and those for I-123-IMZ (4 h, 0.83 +/- 0.19 for 1-C-14-octanoate and 0.57 +/- 0.13 for I-123-IMZ, P < 0.0001; 24 h, 0.91 +/- 0.13 for 1-C-14-octanoate and 0.73 +/- 0.06 for I-123-IMZ, P < 0.0001). Conclusion: 1-C-14-Octanoate uptake was relatively preserved in the regions without morphologic changes despite reduced I-123-IMP and I-123-IMZ uptake. 1-C-11-Octanoate may provide further functional information on the pathophysiology of ischemic stroke, reflecting astroglial function based on fatty acid metabolism.
• Reduction of coronary flow reserve in areas with and without ischemia on stress perfusion imaging in patients with coronary artery disease: A study using oxygen 15-labeled water PET

  K Yoshinaga, C Katoh, K Noriyasu, Y Iwado, H Furuyama, Y Ito, Y Kuge, T Kohya, A Kitabatake, N Tamaki

  JOURNAL OF NUCLEAR CARDIOLOGY 10 (3) 275 - 283 1071-3581 2003/05 [Refereed][Not invited]
   

  Background. Myocardial perfusion single photon emission computed tomography (SPECT) occasionally fails to detect coronary stenosis in patients with coronary artery disease (CAD). We evaluated coronary flow reserve (CFR) using oxygen 15-labeled water in areas with and without ischemia on technetium 99m tetrofosmin stress perfusion SPECT in patients with angiographically documented CAD. Methods and Results. Twenty-seven patients with CAD and eleven age-matched normal subjects were studied. Baseline myocardial blood flow (MBF),and MBF during hyperemia induced by intravenous adenosine triphosphate infusion (0.16 mg (.) kg(-1) (.) min(-1)) were determined with the use of O-15-labeled water positron emission tomography, and the CFR was calculated. Tc-99m tetrofosmin stress/rest SPECT was performed for comparison. On the basis of the results of coronary angiography and SPECT, coronary segments were divided into 3 types: segments with coronary stenosis and a perfusion abnormality on stress SPECT imaging (group A, n = 16), segments with coronary stenosis without a perfusion abnormality (group B, n = 42), and remote segments with no coronary stenosis or perftision abnormality (group C, n 18). Baseline MBF values were similar among the 3 groups. CFR in group A was lower (1.82 +/- 0.54) than in group B (2.22 +/- 0.87, P < .05), in group C (2.92 +/- 1.21, P < .01), and in normal segments (3.86 +/- 1.24, P < .001). CFR in group B was lower than in group C (P < .02) and in normal segments (P < .001). CFR in group C was lower than in normal segments (P < .02). Conclusions. Areas with a perfusion abnormality on stress SPECT had reduced CFR. In the areas without a perfusion abnormality and with coronary stenosis, lowering of CFR was intermediate between the areas with a perfusion abnormality and remote segments. Moreover, CFR was slightly, but significantly, lower in remote segments in patients with CAD compared with normal segments.
• Cyclooxygenase-2 expression associated with spreading depression in a primate model

  C Yokota, H Inoue, Y Kuge, T Abumiya, M Tagaya, Y Hasegawa, N Ejima, N Tamaki, K Minematsu

  JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM 23 (4) 395 - 398 0271-678X 2003/04 [Refereed][Not invited]
   

  The authors previously provided evidence that spreading depression (SD) can be evoked in primates. Cyclooxygenase-2 (COX-2) expression has been found to increase in the rodent cortex undergoing SD, and the authors sought to determine whether this association exists in primate brain. In the present study, neuronal COX-2 expression was induced during SD in the primate cortex. The mean expression ratio of COX-2 messenger RNA in animals with SD was significantly higher than that measured in controls (1.69 vs. 0.5; P = 0.02). Induction of COX-2 in these animals was also detected by human microarray analysis. Results show that, as in rodents, neuronal COX-2 is induced in the primate cortex in response to SD.
• Dominant-negative hypoxia-inducible factor-1 alpha reduces tumorigenicity of pancreatic cancer cells through the suppression of glucose metabolism

  J Chen, SJ Zhao, K Nakada, Y Kuge, N Tamaki, F Okada, JX Wang, M Shindo, F Higashino, K Takeda, M Asaka, H Katoh, T Sugiyama, M Hosokawa, M Kobayashi

  AMERICAN JOURNAL OF PATHOLOGY 162 (4) 1283 - 1291 0002-9440 2003/04 [Refereed][Not invited]
   

  In the tumor cells exposed to hypoxia, hypoxia-inducible factor-1 (HIF-1)-mediated adaptation responses such as angiogenesis and anaerobic metabolism are induced for their survival. We have recently reported that the constitutive expression of HIF-1alpha renders pancreatic cancer cells resistant to apoptosis induced by hypoxia and glucose deprivation. We then established dominant-negative HIF-1alpha (dnHIF-1alpha) transfectants and examined their susceptibility to apoptosis and growth inhibition induced by hypoxia and glucose deprivation in vitro and their tumorigenicity in SCID mice. We further examined the expressions of aldolase A and Glut-1 in vitro and Glut-1 expression and glucose uptake in the tumor tissues and microvessel counts in the tumor tissues. As a result, dnHIF-1alpha rendered the pancreatic cancer cells sensitive to apoptosis and growth inhibition induced by hypoxia and glucose deprivation. Also it abrogated the enhanced expression of Glut-1 and aldolase A mRNAs under hypoxia and reduced the expression of Glut-1 and the glucose uptake in the tumor tissues and consequently in vivo tumorigenicity. We found no significant difference in the microvessel counts among the tumor tissues. From these results, we suggest that the disruption of the HIF-1 pathway Iight be effective in the treatment of pancreatic cancers.
• Post-ischemic cyclooxygenase-2 expression is regulated by the extent of cerebral blood flow reduction in non-human primates

  C Yokota, Y Kuge, H Inoue, M Tagaya, G Kito, T Susumu, N Tamaki, K Minematsu

  NEUROSCIENCE LETTERS 341 (1) 37 - 40 0304-3940 2003/04 [Refereed][Not invited]
   

  We determined whether up to 24 h of ischemia could induce the expression of cyclooxygenase-2 (COX-2) in the brain of nonhuman primates. Randomized animals were subjected to either a 2 h ischemia (group II; n,= 3) or a 24 h ischemia (group 111; n = 3). Three animals in group I served as controls. In group 111, regional cerebral blood flow (CBF) and the cerebral glucose metabolic rate (CMRglc) were evaluated using positron emission tomography. Upregulation of COX-2 mRNA expression was observed after 2 h of ischemia, but disappeared by 24 h in the ischemic temporal cortex, in which both CMRglc and CBF were markedly reduced. In the ischemic parietal cortex, where CMRglc was preserved, COX-2 expression persisted even 24 h after ischemia. This study is the first to demonstrate neuronal COX-2 induction within potentially viable hypoperfused brain areas in nonhuman primates. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.
• Estimation of myocardial blood flow and myocardial flow reserve by Tc-99m-sestamibi imaging: comparison with the results of [O-15]H2O PET

  Y Ito, C Katoh, K Noriyasu, Y Kuge, H Furuyama, K Morita, T Kohya, A Kitabatake, N Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 30 (2) 281 - 287 1619-7070 2003/02 [Refereed][Not invited]
   

  We developed a noninvasive method to quantitatively estimate the myocardial blood flow (MBF) index and flow reserve (MFR) using dynamic and static data obtained with technetium-99m sestamibi, and compared the results with MBF and MFR measured by oxygen-15-labeled water ([O-15]H2O) PET. Twenty patients with coronary artery disease (CAD) and nine normal subjects underwent both Tc-99m-sestamibi and PET studies within 2 weeks. From the anterior view, dynamic data were acquired for 2 min immediately after the injection of Tc-99m-sestamibi, and planar static images were also obtained after 5 min at rest and during ATP stress (0.16 mg kg(-1) min(-1) for 5 min) on another day. The area under the time-activity curve on the aortic arch (Aorta ACU), myocardial weight with the SPET image (M), and the myocardial count on the planar image for 1 min (C-m) were obtained. The MBF index (MBFI) was calculated as follows: MBFI=C-m/Aorta ACUx100/M. MFR was measured by dividing the MBFI at ATP stress by MBFI at rest. The MBFI measured by Tc-99m-sestamibi was significantly correlated with MBF obtained using [O-15]H2O PET (MBFI=13.174+11.732xMBF, r=0.821, P<0.001). Furthermore, MFR measured by Tc-99m-sestamibi was well correlated with that obtained using [O-15]H2O PET, with some underestimation (r=0.845, P<0.001). MFR using Tc-99m-sestamibi in patients with CAD was significantly lower than that in normal subjects (CAD: 1.484+/-0.256 vs normal: 2.127+/-0.308, P<0.001). These data suggest that the MBFI and MFR can be measured with Tc-99m-sestamibi. This may be useful for the quantitative assessment of CAD, especially in those patients with diffuse coronary disease.
• Altered myocardial flow reserve and endothelial function late after Kawasaki disease

  H Furuyama, Y Odagawa, C Katoh, Y Iwado, Y Ito, K Noriyasu, M Mabuchi, K Yoshinaga, Y Kuge, K Kobayashi, N Tamaki

  JOURNAL OF PEDIATRICS 142 (2) 149 - 154 0022-3476 2003/02 [Refereed][Not invited]
   

  Objectives Coronary arterial lesions after Kawasaki disease (KD) may cause coronary endothelial dysfunction as the result of intimal hypertrophy. Our purpose was to assess myocardial flow reserve (MFR) and endothelial function in various myocardial regions after KD by using positron emission tomography. Study design Twenty-seven patients, 17.2 +/- 3.2 years of age, who had KD at 1.9 +/- 1.4 years, and 12 normal healthy subjects, 26.5 +/- 3.4 years of age, were evaluated by means of myocardial blood flow (MBF) with O-15-water positron emission tomography. MFR was estimated by MBF changes under adenosine triphosphate infusion and endothelial function by MBF changes under cold pressor testing. The left ventricle was divided into three coronary territories. Ten stenotic regions, 20 aneurysmal regions, 30 regressed aneurysmal regions, and 21 regions without coronary arterial lesions were compared with 36 control regions of the normal volunteers. Results MBF at rest was similar in each region. Hyperemic blood flow and MFR in each region after KD was significantly lower than those in the regions of normal volunteers. MBF during cold pressor testing was significantly reduced in each region after KD, as compared with no change in the control regions., Conclusions Our study indicates impaired MFR and endothelial function regardless of coronary artery status after KD.
• Detection of apoptotic tumor response in vivo after a single dose of chemotherapy with Tc-99m-annexin V

  T Mochizuki, Y Kuge, SJ Zhao, E Tsukamoto, M Hosokawa, HW Strauss, FG Blankenberg, JF Tait, N Tamaki

  JOURNAL OF NUCLEAR MEDICINE 44 (1) 92 - 97 0161-5505 2003/01 [Refereed][Not invited]
   

  Annexin V, a human protein with a high affinity for phosphatidylserine, has been labeled with Tc-99m to detect apoptosis in vivo. To determine the effectiveness of imaging with this agent as a reflection of the degree of apoptosis after the first dose of chemotherapy, we studied rats with an engrafted hepatoma. Methods: Annexin V was labeled with 99mTc (specific activity, 3.0 MBq/mug protein). Eleven days after being inoculated with allogenic hepatoma cells (KDH-8) in the left calf muscle, the rats were randomized to receive a single dose of cyclophosphamide (150 mg/kg intraperitoneally) or to serve as controls. Tc-99m-annexin V was injected 20 h later. Radioactivity in tissues was determined 6 h after injection of 99mTc-annexin V. Tumor uptake of C-14-iodoanitpyrine was determined as a marker of tumor blood flow. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) of tissue harvested at necropsy was performed to detect apoptosis in the tumor. Results: Cyclophosphamide treatment significantly increased the tumor uptake (percentage activity of injected dose per gram of tissue after normalization to the animal's weight [%ID/g/kg]) of Tc-99m-annexin V (0.070 +/- 0.007 %ID/g/kg for treated rats and 0.046 +/- 0.009 %ID/g/kg for controls, P < 0.001). C-14-iodoantipyrine uptake was similar in the treated and untreated groups. The number of TUNEL-positive cells in the tumor was significantly larger in the treated rats (297.70 +/- 50.34 cells/mm(2)) than in the control rats (168.45 +/- 23.60 cells/mm(2), P < 0.001). Tumor uptake of 99mTc-annexin V correlated with the number of TUNEL-positive cells in the tumor (r = 0.712; P < 0.001). Conclusion: Tumor uptake of Tc-99m-annexin V was Significantly increased by a single dose of cyclophosphamide treatment, and the increase was concordant with the number of TUNEL-positive cells in the tumor. The current results are suggestive of the utility of Tc-99m-annexin V as a noninvasive means to assess tumor response, although further testing, including clinical evaluation, is
• Accumulation of [C-11]acetate in normal prostate and benign prostatic hyperplasia: comparison with prostate cancer

  T Kato, E Tsukamoto, Y Kuge, T Takei, T Shiga, N Shinohara, C Katoh, K Nakada, N Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 29 (11) 1492 - 1495 1619-7070 2002/11 [Refereed][Not invited]
   

  Carbon-11 acetate positron emission tomography (PET) has been reported to be of clinical value for the diagnosis of prostate cancer. However, no detailed analysis has yet been carried out on the physiological accumulation of [C-11]acetate in the prostate. The purpose of this study was to elucidate the physiological accumulation of [C-11]acetate in the prostate using dynamic PET. The study included 30 subjects without prostate cancer [21 with normal prostate and nine with benign prostatic hyperplasia (BPH)] and six patients with prostate cancer. A dynamic PET study was performed for 20 min after intravenous administration of 555 MBq of [C-11]acetate. The standardised uptake value (SUV) at 16-20 min post tracer administration and the early-to-late-activity ratio of the SUV (E/L ratio), which was determined by dividing the SUV6-10 min by the SUV16-20min, were calculated to evaluate the accumulation of [C-11]acetate. The prostate was clearly visualised and distinguished from adjacent organs in PET images in most of the cases. The SUV of the prostate (2.6+/-0.8) was significantly higher than that of the rectum (1.7+/-0.4) or bone marrow (1.3+/-0.3) (P<0.0001 in each case). The SUV of the normal prostate of subjects aged <50 years (3.4+/-0.7) was significantly higher than both the SUV for the normal prostate of subjects aged greater than or equal to50 years (2.3+/-0.7) and that of subjects with BPH (2.1+/-0.6) (P<0.01 in each case). The primary prostate cancer in six cases was visualised by [C-11]acetate PET. However, the difference in the SUV between subjects aged greater than or equal to50 with normal prostate or with BPH and the patients with prostate cancer (1.9+/-0.6) was not statistically significant. There was also no significant difference in the E/L ratio between subjects aged greater than or equal to50 with normal prostate (0.98+/-0.04) or BPH (0.96+/-0.08) and patients with prostate cancer (1.02+/-0.12). In conclusion, a normal prostate exhibits age-related physiological accumulation of [C-11]acetate. Careful interpretation of [C-11]acetate PET images of prostate cancer is necessary because the SUV and the E/L ratio for the normal prostate and for BPH overlap significantly with those for prostate cancer.
• Thermodynamically controlled photocycloaddition of 5-fluoro-1,3-dimethyluracil to naphthalenes

  K Ohkura, T Sugaol, A Sakushima, K Nishijima, Y Kuge, K Seki

  HETEROCYCLES 58 595 - 600 0385-5414 2002/11 [Refereed][Not invited]
   

  UV-Irradiation of 5-fluoro-1,3-dimethyluracil (5-FDMU) and 1-acetonaphthone (1a) afforded trans- 1,4-adduct, ethenobenzoquinazoline, (2) having an acetyl group at the C-10 bridgehead carbon, together with the cis-isomer (3). The cis-adduct (3) is more fragile than 2 in the dark at ambient temperature, and is more quickly converted back to the starting la and 5-FDMU through cycloreversion. Thus, the trans-adduct (2) comes to the predominant product when irradiation is prolonged. Similar irradiation of 1-naphthonitrile afforded cis-ethenobenzoquinazoline-10-carbonitrile (6) and the trans-isomer (7) as the kinetically controlled cycloadducts together with cis-ethenobenzoquinazoline with a CN group on the benzene moiety (5) as thermodynamically controlled product.
• Value and limitation of myocardial fluorodeoxyglucose single photon emission computed tomography using ultra-high energy collimators for assessing myocardial viability

  M Mabuchi, N Kubo, K Morita, K Noriyasu, Y Itoh, C Katoh, Y Kuge, N Tamaki

  NUCLEAR MEDICINE COMMUNICATIONS 23 (9) 879 - 885 0143-3636 2002/09 [Refereed][Not invited]
   

  Single photon emission computed tomography (SPECT) using ultra-high energy collimators permits wide clinical application of 18 F-fluorodeoxyglucose (FDG) imaging without the use of expensive positron emission tomography (PET) cameras. This study was designed to evaluate the value of FDG SPECT using ultra-high energy collimators in assessing myocardial viability compared with FDG PET on a regional basis. We prospectively studied 33 patients with ischaemic heart disease. The patients were injected with 555 MBq of FDG under a hyperinsulinaemic glucose clamp, and FDG PET was performed 40 min later. FDG SPECT using ultra-high energy collimators was performed immediately after FDG PET. The images of the left ventricular myocardium were divided into nine segments and the regional defect score was assessed visually using a four-point scale (0 = normal to 3 = defect). Regional FDG uptake (%uptake) was quantitatively analysed using polar maps. In 297 segments of all the 33 patients, agreement between the defect scores based on FDG SPECT images and those based on FDG PET images was 70%, and agreement within one rank was 96% (kappa value= 0.52). The %uptake based on FDG SPECT images significantly correlated with that based on FDG PET images (r = 0.77, P < 0.01). However, the defect scores in the inferior wall based on FDG SPECT images were higher (1.41+/-1.14) than those based on FDG PET images (1.06+/-1.12, P<0.01). When the viable region is defined as %uptake greater than or equal to50% in FDG PET studies, the optimal cut-off level of %uptake based on FDG SPECT images was 60% in the anterior wall, apex, septum and lateral wall (accuracies, 97%, 93%, 96% and 99%, respectively), and 45% in the inferior wall (accuracy, 99%). It is concluded that FDG SPECT using ultra-high energy collimators can be used for the assessment of myocardial viability as accurately as FDG PET. However, a slight difference was observed in the defect scores mainly due to attenuation in the inferior wall. Therefore, a slightly different cut-off level for assessing myocardial viability should be applied to the inferior wall when using FDG SPECT. ((C) 2002 Lippincott Williams Wilkins).
• Decreased endothelium-dependent coronary vasomotion in healthy young smokers

  Y Iwado, K Yoshinaga, H Furuyama, Y Ito, K Noriyasu, C Katoh, Y Kuge, E Tsukamoto, N Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 29 (8) 984 - 990 1619-7070 2002/08 [Refereed][Not invited]
   

  Chronic cigarette smoking alters coronary vascular endothelial response. To determine whether altered response also occurs in young individuals without manifest coronary disease we quantified coronary blood flow at rest, following adenosine vasodilator stress and during the cold pressor test in healthy young smokers. Myocardial blood flow (MBF) was quantified by oxygen-15 labelled water positron emission tomography in 30 healthy men aged from 20 to 35 years (18 smokers and 12 non-smokers, aged 27.4 +/- 4.4 vs 26.3 +/- 3.3). The smokers had been smoking cigarettes for 9.4 +/- 4.9 pack-years, MBF was measured at rest, during intravenous adenosine triphosphate (ATP: 0.16 mg kg(-1) min(-1)) infusion (hyperaemic response), and during cold pressor test (CPT) (endothelial vasodilator response). Rest MBF and hyperaemic MBF did not differ significantly between the smokers and the non-smokers (rest: 0.86 +/- 0.11 vs 0.92 +/- 0.14 and ATP: 3.20 +/- 1.12 vs 3.69 +/- 0.76 ml g(-1) min(-1); P=NS). Coronary flow reserve was similar between the two groups (smokers: 3.78 +/- 1.83; non-smokers: 4.03 +/- 0.68; P=NS). Although CPT induced a similar increase in rate-pressure product (RPP) in the smokers and the non-smokers (10,430 +/- 1,820 vs 9,236 +/- 1,356 beats min(-1) mmHg(-1)), CPT MBF corrected by RPP was significantly decreased in the smokers (0.65 +/- 0.12 ml g(-1) min(-1)) compared with the non-smokers (0.87 +/- 0.12 ml g(-1) min(-1)) (P<0.05). In addition, the ratio of CPT MBF to resting MBF was inversely correlated with pack-years (r=-0.57, P=0.014). Endothelium-dependent coronary artery vasodilator function is impaired in apparently healthy young smokers.
• Clinical role of F-18-FDG PET for initial staging of patients with extrahepatic bile duct cancer

  T Kato, E Tsukamoto, Y Kuge, C Katoh, T Nambu, A Nobuta, S Kondo, M Asaka, N Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 29 (8) 1047 - 1054 1619-7070 2002/08 [Refereed][Not invited]
   

  In extrahepatic bile duct cancer, preoperative evaluation is important because only surgical excision of all detectable tumours is associated with improvement in 5-year survival. However, morphological imaging techniques, including computed tomography (CT), are still insufficient for accurate staging. The purpose of this study was to assess the additional value, in relation to CT, of 2-[F-18]fluoro-2-deoxy-D-glucose positron emission tomography (F-18-FDG PET) for the evaluation of extrahepatic bile duct cancer. Thirty patients with extrahepatic bile duct cancer underwent both F-18-FDG PET and CT for initial staging. The results of the two modalities for evaluation of primary tumours and regional lymph nodes were compared with the final diagnoses based on pathological or clinical findings. The primary tumours were interpreted as malignant on the basis of CT in 24 (80%) of the patients, while F-18-FDG PET revealed increased F-18-FDG uptake in 18 (60%) of them. On the other hand, F-18-FDG PET showed focal accumulation of F-18-FDG in the bile duct in three of the six patients with equivocal findings on CT. The sensitivity, specificity and accuracy of CT for regional lymph node metastases were 54%, 59% and 57%, while those of F-18-FDG PET were 38%, 100% and 73%, respectively. The specificity of F-18-FDG PET for regional lymph node metastases was significantly higher than that of CT (P<0.01). Of 14 patients with N1 or N2 disease diagnosed by CT, only seven (50%) had a final diagnosis of regional lymph node metastasis. In these 14 patients, F-18-FDG PET accurately evaluated the N component of the disease in 12 patients (86%). In conclusion, in the initial staging of patients with extrahepatic bile duct cancer, F-18-FDG PET offers additional value in relation to CT in evaluating both the primary tumour and regional lymph nodes.
• Increased [F-18]2-fluoro-2-deoxy-D-glucose ([F-18]FDG) yield with recycled target [O-18]water: factors affecting the [F-18]FDG yield

  K Nishijima, Y Kuge, E Tsukamoto, K Seki, K Ohkura, Y Magata, A Tanaka, K Nagatsu, N Tamaki

  APPLIED RADIATION AND ISOTOPES 57 (1) 43 - 49 0969-8043 2002/07 [Refereed][Not invited]
   

  The reuse of [O-18] water after being purified by distillation has been reported to gibe lower [F-18]2-fluoro-2-deoxy-D-glucose ([F-18]FDG) yields. probably due to the presence of organic impurities, In our routine production of [F-18]FDG, however, we observed increased [F-18]FDG yields with recycled [O-18]water. Thus, factors affecting [F]FDG yield were examined using as-purchased (virgin) and recycled (by photochemical combustion and distillation) [O-18]water. [F-18]FDG was synthesized by nucleophilic F-18-fluorination on a quaternary 4-aminopyridinium resin. The recycled [O-18]water gave an [F-18]FDG yield significantly higher than did the virgin water. without any significant difference in the [F-18]fluoride yield. Levels of several ionic impurities including Cl- and Ca2+ were significantly higher in the virgin [O-18]water than in the recycled water, while significantly larger amounts of organic impurities were detected in the former. Hence, trace amounts of organic impurities were not responsible for the lower [F-18]FDG yield. Chloride anion in the [O-18]water may compete with [F-18]fluoride to lower the [F-18]FDG yield. (C) 2002 Elsevier Science Ltd. All rights reserved.
• Low-dose dobutamine stress gated SPET for identification of viable myocardium: comparison with stress-rest perfusion SPET and PET

  K Yoshinaga, C Katoh, K Noriyasu, S Yamada, Y Ito, Y Kuge, Y Kawai, T Kohya, A Kitabatake, N Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 29 (7) 882 - 890 1619-7070 2002/07 [Refereed][Not invited]
   

  The detection of viable myocardium is important for the prediction of functional recovery after revascularisation. However, a fixed perfusion defect often includes viable myocardium, and perfusion imaging then underestimates myocardial viability. We previously reported that low-dose dobutamine stress gated single-photon emission tomography (SPET) provides similar findings to dobutamine stress echocardiography in the assessment of myocardial viability. The present study investigated whether low-dose dobutamine stress gated SPET is of additional value as compared with stress-rest technetium-99m tetrofosmin SPET for the detection of myocardial viability. Standard stress-rest perfusion SPET, low-dose dobutamine stress gated SPET and fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) were studied in 23 patients (mean age 67+/-7.6 years) with previous myocardial infarction. Twenty-one of them were successfully studied with each technique. FDG PET viability (FDG uptake greater than or equal to50%) was employed as the gold standard. One-day stress-rest Tc-99m-tetrofosmin myocardial SPET was performed. After the resting study, gated SPET was acquired following infusion of 7.5 mug kg(-1) min(-1) of dobutamine. Left ventricular wall motion in 16 segments was assessed by cine mode display using a four-point scale. Myocardial viability was considered present when there was improvement by one point. Of a total of 336 segments analysed, 53 had persistent defects on stress-rest perfusion SPET. FDG viability was seen in 16 of 17 dobutamine-responsive segments, but in only 11 of 36 dobutamine non-responsive segments (P<0.01). Thus, in the segments with persistent defects, viability findings on low-dose dobutamine stress gated SPET were concordant with those on FDG PET in 77% of segments (kappa value =0.55). For the detection of FDG-viable myocardium, the combination of stress-rest perfusion SPET and low-dose dobutamine stress gated SPET achieved a better sensitivity than stress-rest perfusion SPET alone (35/46, 76% vs 19/46, 41.3%, P<0.001), with a similar specificity (25/29, 86% vs 26/29, 90%, P=NS). We conclude that in the identification of viable myocardium, low-dose dobutamine stress gated SPET may provide additional information missed on a routine stress-rest perfusion scan. Dobutamine stress gated SPET may provide new insights into myocardial viability on the basis of ischaemia and contractile reserve.
• Unique profile of spreading depression in a primate model

  C Yokota, Y Kuge, Y Hasegawa, M Tagaya, T Abumiya, N Ejima, N Tamaki, T Yamaguchi, K Minematsu

  JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM 22 (7) 835 - 842 0271-678X 2002/07 [Refereed][Not invited]
   

  Spreading depression (SD) is considered to play a role in pathologic conditions of humans such as in the evolution of ischemic brain injury and migraine aura. Because many studies have demonstrated spreading hypoperfusion in patients with migraine and persistent hypoperfusion in nonprimate animal models of SD, these changes in cerebral blood flow (CBF) were regarded as an epiphenomenon of SD. However, there is no direct evidence of the occurrence of SD in primates. The authors attempted to elicit SD by applying 3.3 mol/L potassium chloride to the cerebral cortex of nine male cynomolgus monkeys. The CBF was monitored by positron emission tomography in five animals. Propagated direct-current shifts were found by the two neighboring microelectrodes only in one animal. The direct-current wave propagated at a speed of 4 mm/min and its amplitude was 20 mV, being consistent with the SD findings. Except in one animal with 6 SD episodes, SD waves were recorded infrequently at the rostral site (none in three animals, once in three, and twice in two). Focal hyperemia accompanied SD. Neither spreading hypoperfusion nor persistent hypoperfusion was found. These unique features of SD in primates raise a doubt as to whether the role of SD in nonprimate animals is the same as that in stroke and migraine in humans.
• Fluorodeoxyglucose uptake and glucose transporter expression in experimental inflammatory lesions and malignant tumours: effects of insulin and glucose loading

  S Zhao, Y Kuge, E Tsukamoto, T Mochizuki, T Kato, K Hikosaka, K Nakada, M Hosokawa, M Kohanawa, N Tamaki

  NUCLEAR MEDICINE COMMUNICATIONS 23 (6) 545 - 550 0143-3636 2002/06 [Refereed][Not invited]
   

  The expression of glucose transporters (GLUTs) and its relationship to fluorodeoxyglucose accumulation in malignant tun-tours have been well investigated, while such a relation has not been studied in inflammatory lesions. The aim of the present study was to investigate the effects of insulin and glucose loading on the expression of GLUTs in inflammatory lesions and compare them with those in malignant tumours in relation to fluorodeoxyglucose accumulation. All tissue specimens used in this study were obtained in our previous study, in which rats were inoculated with allogenic hepatoma cells (KDH-8), Staphylococcus aureus, or turpentine oil into the left calf muscle and divided into three subgroups: insulin loaded, glucose loaded, and control groups. The expression of glucose transporters (GLUT-1 to GLUT-5) was investigated by immunostaining the lesions (n = 5-6, for each group). In all control groups, the expression levels of GLUT-1 and GLUT-3 were significantly higher than those of GLUT-2, GLUT-4 and GLUT-5. Insulin loading did not significantly affect the expression levels of GLUT-1 and GLUT-3 in these lesions except for a significant but slight decrease in the GLUT-1 expression level in the inflammatory lesion of non-infectious origin (89% of the control value). Glucose loading significantly decreased the expression level of GLUT-1 in the inflammatory lesion of non-infectious origin (70% of the control value, P < 0.01), and that of GLUT-3 in the inflammatory lesion of infectious origin (70% of the control value, P < 0.05), while the expression levels of GLUT-1 and GLUT-3 in the tumour were not significantly affected. These results demonstrate the effects of insulin and glucose loading on the expression level of a molecule (GLUT proteins). The decreased GLUT-1 and GLUT-3 expression levels induced by glucose loading may partly explain the impaired FDG uptake observed in our previous study. ((C) 2002 Lippincott Williams Wilkins).
• Assessment of coronary function in children with a history of Kawasaki disease using O-15-water positron emission tomography

  H Furuyama, Y Odagawa, C Katoh, Y Iwado, K Yoshinaga, Y Ito, K Noriyasu, M Mabuchi, Y Kuge, K Kobayashi, N Tamaki

  CIRCULATION 105 (24) 2878 - 2884 0009-7322 2002/06 [Refereed][Not invited]
   

  Background-Coronary abnormalities after Kawasaki disease (KD) may be associated with endothelial dysfunction due to intimal hypertrophy. The purpose of this study was to evaluate myocardial flow reserve (MFR) and endothelial function in regressed aneurysmal regions after KD. Methods and Results-Subjects were 12 patients aged 16.0+/-2.6 years who suffered from KD at 1.7+/-1.5 years and 12 normal subjects aged 26.5+/-3.4 years. MFR and endothelial function were estimated, respectively, by changes in myocardial blood flow (MBF) during ATP infusion and by that during cold pressor test using O-15-water positron emission tomography. Data from 24 regressed aneurysmal regions were compared with those from the corresponding regions (n=36) in the control group. Although the MBF at rest in the regressed aneurysmal regions was similar to that in controls, the MBF at a hyperemic state induced by ATP infusion in the regressed aneurysmal regions was significantly lower than that in the control regions. Therefore, the MFR in regressed aneurysmal regions was significantly lower than that in controls (3.53+/-0.95 versus 4.60+/-1.14; P<0.05). MBF at rest and during the cold pressor test did not change in the control regions, but it was significantly reduced in regressed aneurysmal regions. The ratio of MBF during the cold pressor test to MBF at rest was significantly lower in regressed aneurysmal regions than in control regions (0.67+/-0.15 versus 1.00+/-0.15; P<0.05). Conclusions-MFR and endothelial function are often impaired in regressed aneurysmal regions after KD, and tomography enables the noninvasive evaluation of coronary function.
• Intense F-18FDG accumulation in the stomach in a patient with Menetrier's disease

  T Kato, Y Komatsu, E Tsukamoto, M Takei, T Takei, F Yamamoto, Y Kuge, M Asaka, N Tamaki

  CLINICAL NUCLEAR MEDICINE 27 (5) 376 - 377 0363-9762 2002/05 [Refereed][Not invited]
   

  Menetrier's disease is a rare disorder that is characterized by significant hypertrophy of the gastric mucosa accompanied by hypoproteinemia caused by the loss of proteins from the gastric mucosa. To the authors' knowledge, the F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) findings of Menetrier's disease have not been reported. They present F-18 FDG-PET images of a patient with Menetrier's disease that show intense accumulation of F-18 FDG in the stomach that is likely to indicate a malignant disease of the stomach.
• Quantitative evaluation of the relative contribution ratio of cerebral tissue to near-infrared signals in the adult human head: a preliminary study

  S Kohri, Y Hoshi, M Tamura, C Kato, Y Kuge, N Tamaki

  PHYSIOLOGICAL MEASUREMENT 23 (2) 301 - 312 0967-3334 2002/05 [Refereed][Not invited]
   

  Combining spatially- and time-resolved spectroscopies, we attempted to quantitatively evaluate the contribution ratio of the partial mean pathlength of cerebral tissue to the observed overall mean pathlength, in which haemoglobin concentrations were selectively changed by administration of acetazolamide. When acetazolamide was administered, the observed increases in oxygenated haemoglobin depended on the probe distance, which became progressively larger at distances of 2, 3 and 4 cm. Increases in oxygen saturation were detected at 3 and 4 cm spacing, but not at 2 cm. Assuming that the modified Lambert-Beer's law can exist in the inhomogeneous structure of the head, then, we could estimate the contribution ratio of the cerebral tissue to optical signals at the probe distances of 2, 3 and 4 cm as 33%, 55% and 69%, respectively. Using these values, we recalculated acetazolamide-induced concentration changes in oxygenated-haemoglobin in the cerebral tissue, which resulted in the same values at distances of 2, 3 and 4 cm as expected. Thus, our present method opened the door to the possibility of selectively obtaining optical signals attributed to cerebral tissue.
• Stereoselective synthesis of 4a-fluoro-5,10-ethenobenzo[f]quinazolines via photo-Diels-Alder reaction of 5-fluoro-1,3-dimethyluracil with naphthalenes

  K Ohkura, T Sugaoi, K Nishijima, Y Kuge, K Seki

  TETRAHEDRON LETTERS 43 (17) 3113 - 3115 0040-4039 2002/04 [Refereed][Not invited]
   

  UV-irradiation of a solution of 5-fluoro-1,3-dimethyluracil (5-FDMU) in aprotic media effected a stereoselective 1,4-cycloaddition reaction to give a barrelene derivative in high yield. In direct contrast, irradiation of a solution of 5-FDMU and naphthalene in a protic medium afforded 5-(1-naphthyl)uracil as the major product. (C) 2002 Elsevier Science Ltd. All rights reserved.
• A simplified and improved synthesis of [C-11]phosgene with iron and iron (III) oxide

  KI Nishijima, Y Kuge, K Seki, K Ohkura, N Motoki, K Nagatsu, A Tanaka, E Tsukamoto, N Tamaki

  NUCLEAR MEDICINE AND BIOLOGY 29 (3) 345 - 350 0969-8051 2002/04 [Refereed][Not invited]
   

  [C-11]Phosgene ([C-11]COCl2), a useful precursor for labeling several radiopharmaceuticals, is generally produced by catalytic oxidation of [C-11]carbon tetrachloride over Fe granules, although in low yields or with poor reproducibility, In order to develop am improved synthesis of [C-11]phosgene, two oxidizing agents, Fe2O3 and CuO, were examined. The yield of [C-11]phosgene was significantly increased using Fe2O3 Powder mixed with Fe granules. while the use of CuO alone, of CuO powder mixed with Fe granules resulted in an insignificant yield. The yield and specific activity of S- (-) [C-11]CGP-12177 synthesized using Fe2O3 powder mixed with Fe granules were markedly higher than those synthesized by the previous methods using Fe granules alone or Fe granules mixed with Fe powder. Thus, in the present study, we developed a simple and practical method for the synthesis of [C-11]phosgene. which provided an improved yield of S- (-) [C-11]CGP-12177. (C) 2002 Elsevier Science Inc. All rights reserved.
• In vitro uptake of [1-C-14]Octanoate in brain slices of rats: basic studies for assessing [1-(11C)]Octanoate as a PET tracer of glial functions

  Y Kuge, K Hikosaka, K Seki, K Ohkura, K Nishijima, E Tsukamoto, N Tamaki

  NUCLEAR MEDICINE AND BIOLOGY 29 (3) 303 - 306 0969-8051 2002/04 [Refereed][Not invited]
   

  To clarify the contribution of glial cells to octanoate uptake into the brain, we determined the effects of fluoroacetate, a selective inhibitor of glial metabolism, on in vitro brain uptake of [1-C-14]octanoate, using rat brain slices. The [1-C-14]octanoate uptake significantly decreased, depending on the concentration of fluoroacetate (p = 0.001). The; [1-C-14] octanoate uptakes at 5 mM (0.23 +/- 0.05% uptake/mg slice) and 25 mM fluoroacetate (0.12 +/- 0.01% uptake/mg slice) were significantly lower than that at control (0.29 +/- 0.02% uptake/mg slice, p < 0.05 and p < 0.001, respectively). The results demonstrate the contribution of glial cells to octanoate uptake into the brain. The potential of [1-C-11]octanoate as a PET tracer for studying glial functions is suggested. (C) 2002 Elsevier Science Inc. All rights reserved.
• Chemical impurities in [F-18]FDG preparations produced by solid-phase F-18-fluorination

  Y Kuge, K Nishijima, K Nagatsu, K Seki, K Ohkura, A Tanaka, M Sasaki, E Tsukamoto, N Tamaki

  NUCLEAR MEDICINE AND BIOLOGY 29 (2) 275 - 279 0969-8051 2002/02 [Refereed][Not invited]
   

  [F-18]FDG was produced by solid-phase F-18-fluorination (resin method) and chemical impurities were determined in the [F-18]FDG preparations by ion chromatography. The major chemical impurities were D-glucose (90.5 +/- 6.4 mug/mL), 2-chloro-2-deoxy-D-glucose (11.8 +/- 2.7 mug/mL), and D-mannose (1.7 +/- 0.7 mug/mL), which were expected to be present by considering the synthetic routes. An FDG mass (0.5 +/- 0.2 mug/mL) was also detected in the preparations. No notable radiochemical impurities, including 2-[F-18]fluoro-2-deoxy-D-mannose. were detected in the [F-18]FDG preparations. Thus, the levels of several chemical impurities were determined in the [F-18]FDG preparations produced by solid-phase F-18-fluorination. (C) 2002 Elsevier Science Inc. All rights reserved.
• Low-dose dobutamine stress gated SPET for identification of viable myocardium: Comparison with stress-rest perfusion SPET and PET

  Keiichiro Yoshinaga, Chietsugu Katoh, Kazuyuki Noriyasu, Satoshi Yamada, Yoshinori Ito, Yuji Kuge, Yuko Kawai, Tetsuro Kohya, Akira Kitabatake, Nagara Tamaki

  European Journal of Nuclear Medicine 29 (7) 882 - 890 0340-6997 2002 [Refereed][Not invited]
   

  The detection of viable myocardium is important for the prediction of functional recovery after revascularisation. However, a fixed perfusion defect often includes viable myocardium, and perfusion imaging then underestimates myocardial viability. We previously reported that low-dose dobutamine stress gated single-photon emission tomography (SPET) provides similar findings to dobutamine stress echocardiography in the assessment of myocardial viability. The present study investigated whether low-dose dobutamine stress gated SPET is of additional value as compared with stress-rest technetium-99m tetrofosmin SPET for the detection of myocardial viability. Standard stress-rest perfusion SPET, low-dose dobutamine stress gated SPET and fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) were studied in 23 patients (mean age 67±7.6 years) with previous myocardial infarction. Twenty-one of them were successfully studied with each technique. FDG PET viability (FDG uptake ≥50%) was employed as the gold standard. One-day stress-rest 99mTc-tetrofosmin myocardial SPET was performed. After the resting study, gated SPET was acquired following infusion of 7.5 μg kg-1 min-1 of dobutamine. Left ventricular wall motion in 16 segments was assessed by cine mode display using a four-point scale. Myocardial viability was considered present when there was improvement by one point. Of a total of 336 segments analysed, 53 had persistent defects on stress-rest perfusion SPET. FDG viability was seen in 16 of 17 dobutamine-responsive segments, but in only 11 of 36 dobutamine non-responsive segments (P< 0.01). Thus, in the segments with persistent defects, viability findings on low-dose dobutamine stress gated SPET were concordant with those on FDG PET in 77% of segments (kappa value =0.55). For the detection of FDG-viable myocardium, the combination of stress-rest perfusion SPET and low-dose dobutamine stress gated SPET achieved a better sensitivity than stress-rest perfusion SPET alone (35/46, 76% vs 19/46, 41.3%, P< 0.001), with a similar specificity (25/29, 86% vs 26/29, 90%, P=NS). We conclude that in the identification of viable myocardium, low-dose dobutamine stress gated SPET may provide additional information missed on a routine stress-rest perfusion scan. Dobutamine stress gated SPET may provide new insights into myocardial viability on the basis of ischaemia and contractile reserve.
• Clinical role of 18F-FDG PET for initial staging of patients with extrahepatic bile duct cancer

  Takashi Kato, Eriko Tsukamoto, Yuji Kuge, Chietsugu Katoh, Toshikazu Nambu, Aichiro Nobuta, Satoshi Kondo, Masahiro Asaka, Nagara Tamaki

  European Journal of Nuclear Medicine 29 (8) 1047 - 1054 0340-6997 2002 [Refereed][Not invited]
   

  In extrahepatic bile duct cancer, preoperative evaluation is important because only surgical excision of all detectable tumours is associated with improvement in 5-year survival. However, morphological imaging techniques, including computed tomography (CT), are still insufficient for accurate staging. The purpose of this study was to assess the additional value, in relation to CT, of 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) for the evaluation of extrahepatic bile duct cancer. Thirty patients with extrahepatic bile duct cancer underwent both 18F-FDG PET and CT for initial staging. The results of the two modalities for evaluation of primary tumours and regional lymph nodes were compared with the final diagnoses based on pathological or clinical findings. The primary tumours were interpreted as malignant on the basis of CT in 24 (80%) of the patients, while 18F-FDG PET revealed increased 18F-FDG uptake in 18 (60%) of them. On the other hand, 18F-FDG PET showed focal accumulation of 18F-FDG in the bile duct in three of the six patients with equivocal findings on CT. The sensitivity, specificity and accuracy of CT for regional lymph node metastases were 54%, 59% and 57%, while those of 18F-FDG PET were 38%, 100% and 73%, respectively. The specificity of 18F-FDG PET for regional lymph node metastases was significantly higher than that of CT (P< 0.01). Of 14 patients with N1 or N2 disease diagnosed by CT, only seven (50%) had a final diagnosis of regional lymph node metastasis. In these 14 patients, 18F-FDG PET accurately evaluated the N component of the disease in 12 patients (86%). In conclusion, in the initial staging of patients with extrahepatic bile duct cancer, 18F-FDG PET offers additional value in relation to CT in evaluating both the primary tumour and regional lymph nodes.
• Decreased endothelium-dependent coronary vasomotion in healthy young smokers

  Yasuyoshi Iwado, Keiichiro Yoshinaga, Hideto Furuyama, Yoshinori Ito, Kazuyuki Noriyasu, Chietsugu Katoh, Yuji Kuge, Eriko Tsukamoto, Nagara Tamaki

  European Journal of Nuclear Medicine 29 (8) 984 - 990 0340-6997 2002 [Refereed][Not invited]
   

  Chronic cigarette smoking alters coronary vascular endothelial response. To determine whether altered response also occurs in young individuals without manifest coronary disease we quantified coronary blood flow at rest, following adenosine vasodilator stress and during the cold pressor test in healthy young smokers. Myocardial blood flow (MBF) was quantified by oxygen-15 labelled water positron emission tomography in 30 healthy men aged from 20 to 35 years (18 smokers and 12 non-smokers, aged 27.4±4.4 vs 26.3±3.3). The smokers had been smoking cigarettes for 9.4±4.9 pack-years. MBF was measured at rest, during intravenous adenosine triphosphate (ATP: 0.16 mg kg-1 min-1) infusion (hyperaemic response), and during cold pressor test (CPT) (endothelial vasodilator response). Rest MBF and hyperaemic MBF did not differ significantly between the smokers and the non-smokers (rest: 0.86±0.11 vs 0.92±0.14 and ATP: 3.20±1.12 vs 3.69±0.76 ml g-1 min-1 P=NS). Coronary flow reserve was similar between the two groups (smokers: 3.78±1.83 non-smokers: 4.03±0.68 P=NS). Although CPT induced a similar increase in rate-pressure product (RPP) in the smokers and the non-smokers (10,430±1,820 vs 9,236±1,356 beats min-1 mmHg-1), CPT MBF corrected by RPP was significantly decreased in the smokers (0.65±0.12 ml g-1 min-1) compared with the non-smokers (0.87±0.12 ml g-1 min-1) (P< 0.05). In addition, the ratio of CPT MBF to resting MBF was inversely correlated with pack-years (r=-0.57, P=0.014). Endothelium-dependent coronary artery vasodilator function is impaired in apparently healthy young smokers.
• Accumulation of [11C]acetate in normal prostate and benign prostatic hyperplasia: Comparison with prostate cancer

  Takashi Kato, Eriko Tsukamoto, Yuji Kuge, Toshiki Takei, Tohru Shiga, Nobuo Shinohara, Chietsugu Katoh, Kunihiro Nakada, Nagara Tamaki

  European Journal of Nuclear Medicine 29 (11) 1492 - 1495 0340-6997 2002 [Refereed][Not invited]
   

  Carbon-11 acetate positron emission tomography (PET) has been reported to be of clinical value for the diagnosis of prostate cancer. However, no detailed analysis has yet been carried out on the physiological accumulation of [11C]acetate in the prostate. The purpose of this study was to elucidate the physiological accumulation of [11C]acetate in the prostate using dynamic PET. The study included 30 subjects without prostate cancer [21 with normal prostate and nine with benign prostatic hyperplasia (BPH)] and six patients with prostate cancer. A dynamic PET study was performed for 20 min after intravenous administration of 555 MBq of [11C]acetate. The standardised uptake value (SUV) at 16-20 min post tracer administration and the early-to-late-activity ratio of the SUV (E/L ratio), which was determined by dividing the SUV6-10 min by the SUV16-20min, were calculated to evaluate the accumulation of [11C]acetate. The prostate was clearly visualised and distinguished from adjacent organs in PET images in most of the cases. The SUV of the prostate (2.6±0.8) was significantly higher than that of the rectum (1.7±0.4) or bone marrow (1.3±0.3) (P< 0.0001 in each case). The SUV of the normal prostate of subjects aged < 50 years (3.4±0.7) was significantly higher than both the SUV for the normal prostate of subjects aged ≥50 years (2.3±0.7) and that of subjects with BPH (2.1±0.6) (P< 0.01 in each case). The primary prostate cancer in six cases was visualised by [11C]acetate PET. However, the difference in the SUV between subjects aged ≥50 with normal prostate or with BPH and the patients with prostate cancer (1.9±0.6) was not statistically significant. There was also no significant difference in the E/L ratio between subjects aged ≥50 with normal prostate (0.98±0.04) or BPH (0.96±0.08) and patients with prostate cancer (1.02±0.12). In conclusion, a normal prostate exhibits age-related physiological accumulation of [11C]acetate. Careful interpretation of [11C]acetate PET images of prostate cancer is necessary because the SUV and the E/L ratio for the normal prostate and for BPH overlap significantly with those for prostate cancer.
• Synthesis of 9,11-diazapentacyclo[6.4.0.0(1,3).0(2,5).0(4,8)]dodecane-2,4-diones

  K Ohkura, K Nishijima, Y Kuge, K Seki

  HETEROCYCLES 56 (1-2) 235 - 244 0385-5414 2002/01 [Refereed][Not invited]
   

  UV-Irradiation of 5,6-dihydrocyclobutaquinazoline-2,4-dione derivatives (1c-g) furnished the corresponding 9,11-diazapentacyclo[6.4.0.0(1,3).0(2,5).0(4,8)]dodecane-10,12-diones (2c-g) in fair yields, whereas photoreaction of cyclobutaquinazoline-2,4-dione (1h) produced quinazoline-2,4-dione (4) and cyclooctapyrimidine (5).
• FDG uptake and glucose transporter subtype expressions in experimental tumor and inflammation models

  TA Mochizuki, E Tsukamoto, Y Kuge, K Kanegae, SJ Zhao, K Hikosaka, M Hosokawa, M Kohanawa, N Tamaki

  JOURNAL OF NUCLEAR MEDICINE 42 (10) 1551 - 1555 0161-5505 2001/10 [Refereed][Not invited]
   

  Although FDG uptake is closely related to the expression of the glucose transporter (GLUT) in malignant tumors, such a relationship has not been fully investigated in inflammatory lesions. The aim of our study was to determine the expression of GLUT subtypes in experimental inflammatory lesions and to compare the results with those in malignant tumors in relation to FDG accumulation. Methods: Rats were inoculated with a suspension of Staphylococcus aureus or allogenic hepatoma cells (KDH-8) into the left calf muscle. Five days after S. aureus inoculation (n = 9) and 14 d after KDH-8 inoculation (n = 11), [C-14]FDG was Injected intravenously and its accumulation in the infectious and tumor tissues was determined as the percentage activity of the injected dose per gram of tissue (%ID/g). The expression of glucose transporters (GLUT-1 to GLUT-5) was investigated by immunostaining the infectious tissues (n = 6) and the tumor tissues (n = 6). Immunohistochemical grading was assessed semiquantitatively by 5 observers. Results: The [14C]FDG uptake was significantly higher in the tumor lesion than in the inflammatory lesion (2.04 +/- 0.38 %ID/g vs. 0.72 +/- 0.15 %ID/g; P < 0.0001). The tumor and inflammatory tissues highly expressed GLUT-1 and GLUT-3. The GLUT-1 expression level was significantly higher in the tumor tissue than in the inflammatory tissue (P < 0.05). Conclusion: The results based on our models showed a high FDG uptake and high GLUT-1 expression level not only in the tumor lesion but also in the inflammatory lesion. The higher GLUT-1 expression level In the tumor lesion may partially explain the higher FDG accumulation in the tumor than in the inflammatory lesion.
• Low-dose dobutamine electrocardiograph-gated myocardial SPECT for identifying viable myocardium: Comparison with dobutamine stress echocardiography and PET

  K Yoshinaga, K Morita, S Yamada, K Komuro, C Katoh, Y Ito, Y Kuge, T Kohya, A Kitabatake, N Tamaki

  JOURNAL OF NUCLEAR MEDICINE 42 (6) 838 - 844 0161-5505 2001/06 [Refereed][Not invited]
   

  The identification of severely dysfunctional but viable myocardium is of particular importance for the selection of patients with depressed left ventricular function who will benefit from coronary revascularization. Assessment of inotropic reserve with dobutamine has recently been used for this purpose. This study compared the accuracy of low-dose dobutamine stress gated myocardial SPECT (DS SPECT) with the accuracy of dobutamine stress echocardiography (DSE) and resting perfusion SPECT for the identification of viable myocardium in patients with previous myocardial infarction. Methods: Resting and low-dose dobutamine (7.5 mug/kg/min) gated Tc-99m-tetrofosmin SPECT and echocardiography and resting F-18-FDG PET were prospectively studied in 23 patients with previous myocardial infarction and severely depressed regional function. Twenty-one of them were successfully studied with each technique. The left ventricular wall was divided into 14 segments to assess wall motion using a 5-point scale. PET viability was defined as FDG uptake greater than or equal to 50% of the maximum uptake in a region with normal wall motion. For DS SPECT and DSE studies, viable myocardium was defined as hypokinetic areas with greater than or equal to1 point improvement in wall motion. For resting perfusion SPECT, viable myocardium was defined as hypokinetic areas with a relative uptake greater than or equal to 50% of the maximum uptake. Results: Of a total of 294 segments, 55 had severe resting dyskinesis. Thirty-four segments were identified as viable on FDG PET, and 21 segments were identified as nonviable. Eleven segments were inadequately visualized with DSE, including 5 segments in the apex. Sensitivities (78% vs. 76%) and specificities (94% vs. 100%) were similar for DSE and DS SPECT, with a concordance of 86% (kappa = 0.72), DS SPECT and perfusion SPECT did not significantly differ with respect to sensitivities (76% vs. 85%, respectively). However, specificity was significantly higher for DS SPECT than for perfusion SPECT (100% vs. 52%, respectively, P < 0.05). Conclusion: This study indicated that DS SPECT correlates well with DSE in the assessment of viability, In addition, gated SPECT can evaluate regional wall motion, even in areas inadequately assessed by echocardiography. DS SPECT may also provide additional information for identifying viable myocardium, which is often overestimated by routine perfusion scans.
• Effects of insulin and glucose loading on FDG uptake in experimental malignant tumours and inflammatory lesions

  S Zhao, Y Kuge, E Tsukamoto, T Mochizuki, T Kato, K Hikosaka, M Hosokawa, M Kohanawa, N Tamaki

  EUROPEAN JOURNAL OF NUCLEAR MEDICINE 28 (6) 730 - 735 0340-6997 2001/06 [Refereed][Not invited]
   

  Fluorine-18 2-deoxy-2-fluoro-D-glucose (FDG) accumulation in tumours has been well investigated, but much less is known regarding FDG accumulation in inflammatory lesions. In this study, we determined the effects of hypo- and hyperglycaemia on FDG uptake in inflammatory lesions of infectious and non-infectious origin and compared them with those in malignant tumours in rats, to provide a biological basis for differentiating malignant lesions from benign lesions by means of FDG-PET. Rats were inoculated with a suspension of allogenic hepatoma cells (KDH-8) or Staphylococcus aureus, or with turpentine oil into the left calf muscle. Two weeks after KDH-8 inoculation and 1 week after S. aureus and turpentine oil inoculations, the rats were divided into three subgroups: insulin-loaded (2 U/kg body weight, i.p.), glucose-loaded (1.2 g/kg body weight, p.o.) and control groups. Radioactivity in tissues was determined 1 h after i.v. injection of FDG, Intraperitoneal injection of insulin and oral administration of glucose induced hypoglycaemia and hyperglycaemia, respectively. In the control animals, tumours showed a level of FDG uptake which was 2.2 and 3.0 times higher than the levels in the inflammatory lesions induced by S. aureus and turpentine oil, respectively (P <0.0001), There was no significant difference in the level of FDG uptake between the two inflammatory lesions of infectious and non-infectious origin. Insulin loading significantly decreased the level of FDG uptake in tumours and in both types of inflammatory lesion to approximately one-half of the control values (P=0.001 in the tumour group and P<0.0001 in the two inflammatory lesion groups). In the glucose-loaded group, the level of FDG uptake in both types of inflammatory lesion decreased significantly to 50%-61% of the control value (P=0.0002 in the S. aureus group and P<less than>0.0001 in the turpetine group), while the tumour uptake did not decrease significantly (86% of the control value) (P=NS). It is concluded that FDG uptake in both types of inflammatory lesion was significantly impaired in rats with hyperglycaemia induced by glucose loading, while tumour uptake of FDG was not significantly affected. These results indicate that glucose loading has greater effects on FDG uptake in inflammatory lesions than in tumours, providing a biological basis for differentiation of malignant lesions from benign lesions by FDG-PET in a clinical setting.
• オンカラム法(FDG MicroLabTM)を用いる18F-FDGの合成 エンドトキシン試験及び無菌試験に関する検討

  久下 裕司, 西嶋 剣一, 永津 弘太郎, 田中 明, 塚本 江利子, 玉木 長良

  核医学 (一社)日本核医学会 38 (2) 125 - 130 0022-7854 2001/03 [Refereed][Not invited]
   

  オンカラム法に基づくFDG自動合成装置を用いて18F-FDGを合成し, 18F-FDGおよびその製剤成分がエンドトキシン試験(リムルステスト)および無菌試験(血液培養システム)結果に及ぼす影響を検討した.その結果,エンドトキシンを添加した18F-FDG製剤は,対照(注射用生理食塩液)に比べてゲル凝固(比濁法)をわずかに促進させた.他方,微生物菌株と18F-FDG製剤を血液培養システムに摂取・培養した結果,いずれの場合も培養開始後72時間以内に陽性所見が得られ,かつ,18F-FDG製剤群と対照群の間でこれらの所見に差異はなかった.ゲル凝固の促進は判定基準を厳しくするものである.したがって,本法により調製された18F-FDG製剤は,エンドトキシン濃度および無菌性の判定に対して問題となる影響は与えないと考えられた
• Comparison of F-18-FDG, I-131-Na, and Tl-201 in diagnosis of recurrent or metastatic thyroid carcinoma

  T Shiga, E Tsukamoto, K Nakada, K Morita, T Kato, M Mabuchi, K Yoshinaga, C Katoh, Y Kuge, N Tamaki

  JOURNAL OF NUCLEAR MEDICINE 42 (3) 414 - 419 0161-5505 2001/03 [Refereed][Not invited]
   

  There are several reports about the usefulness of F-18-FDG PET in thyroid cancer. However, few studies have compared FDG PET with I-131 and Tl-201 scintigraphy. The aim of this study was to evaluate the clinical significance of whole-body FDG PET in differentiated thyroid cancer and to compare the results with those obtained from I-131 and Tl-201 scintigraphy. Methods: Whole-body FDG PET was performed on 32 patients (10 men, 22 women; age range, 30-77 y; mean age, 54 y) with differentiated thyroid cancer (5 cases of follicular cancer and 27 of papillary cancer) after total thyroidectomy. An overall clinical evaluation was performed, including cytology, thyroglobulin level, sonography, MRI, and CT, to allow a comparison with functional imaging results for each patient. Metastatic regions were divided into five areas: neck, lung, mediastinum, bone, and other. Multiple lesions in one area were defined as one lesion. The tumor-to-background ratio (TBR) was measured for the lesions that were positive for both Tl-201 uptake and FDG PET uptake. Results: The number of lesions totaled 47, Forty-one (87%) were detected by all scintigraphic methods. FDG uptake was concordant with I-131 uptake in only 18 lesions (38%). FDG uptake was concordant with Tl-201 uptake in 44 lesions (94%), Only one lesion was negative for FDG uptake and positive for Tl-201 uptake, and two lesions were positive for FDG uptake and negative for Tl-201 uptake. A significant correlation was seen between the TBR of Tl-201 and that of FDG (r = 0.69; P < 0.05). Conclusion: These data indicate that for detecting metastatic lesions, FDG PET and I-131 scintigraphy may provide complementary information, whereas FDG PET may provide results similar to those of Tl-201 scintigraphy. Thus, the combination of I-131 scintigraphy and FDG PET (or Tl-201 scintigraphy) is the method of choice for detecting metastatic thyroid cancer after total thyroidectomy.
• Serial changes in cerebral blood flow and flow-metabolism uncoupling in primates with acute thromboembolic stroke

  Y Kuge, C Yokota, M Tagaya, Y Hasegawa, A Nishimura, G Kito, N Tamaki, N Hashimoto, T Yamaguchi, K Minematsu

  JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM 21 (3) 202 - 210 0271-678X 2001/03 [Refereed][Not invited]
   

  The authors recently developed a primate thromboembolic stroke model. To characterize the primate model, the authors determined serial changes in cerebral blood flow (CBF) and the relation between CBF and cerebral metabolic rate of glucose (CMRglc) using high-resolution positron emission tomography. Thromboembolic stroke was produced in male cynomolgus monkeys (n = 4). Acute obstruction of the left middle cerebral artery was achieved by injecting an autologous blood clot into the left internal carotid artery. Cerebral blood flow was measured with [O-15]H2O before and 1, 2, 4, 6, and 24 hours after embolization. CMRglc was measured with 2-[F-18]fluoro-2-deoxy-D-glucose ([F-18]FDG) 24 hours after embolization. Lesion size and location 24 hours after embolization was determined by the 2,3,5-triphenyl-tetrazolium chloride (TTC) staining method. The results are summarized as follows: (1) 1 hour after embolization, CBF in the temporal cortex and the basal ganglia decreased to < 40% of the contralateral values. Ln these regions, regarded as an ischemic core, CBF decreased further with time and CMRglc at 24 hours also decreased. Infarcted lesions as indicated by being unstained with TTC were consistently observed in these regions. (2) In the parietal cortex and several regions surrounding the ischemic core, CBF was >40% of the contralateral values 1 hour after embolization and recovered gradually with time (ischemic penumbra). In these regions, CMRglc at 24 hours increased compared with that in the contralateral regions, indicating an uncoupling of CBF and CMRglc. No obvious TTC-unstained lesions were detected in these regions. The authors demonstrated a gradual recovery of reduced CBF, an elevated CMRglc and a CBF-CMRglc uncoupling in the penumbra regions of the primate model. Positron emission tomography investigations using this model will provide better understanding of the pathophysiology of thromboembolic stroke in humans.
• Performance assessment of O-18 water purifier

  H Kitano, Y Magata, A Tanaka, T Mukai, Y Kuge, K Nagatsu, J Konishi, H Saji

  ANNALS OF NUCLEAR MEDICINE 15 (1) 75 - 78 0914-7187 2001/02 [Refereed][Not invited]
   

  In the synthesis of F-18-FDG by the nucleophilic substitution method,O-18-H2O is usually used as target water. The target water should be recovered after synthesis and reused, because it is expensive, but recovered water contains impurities such as organic substances, and it must be purified before reuse. For this reason Sumitomo Heavy Industries, Ltd. developed an O-18 water purifier for elimination of organic substances in recovered water. This instrument consists of a UV irradiation unit and low-temperature distillation unit. Our institution had an opportunity to test use this instrument and evaluated its performance. The concentrations of organic substances after UV irradiation was greatly reduced, and recovery efficiency after distillation by the low-temperature distillation unit was very satisfactory at 99.3 +/- 0.5%. Furthermore, the yield of F-18-FDG from O-18-H2O purified with this instrument was sufficient for the clinical use.
• Experimental thromboembolic stroke in cynomolgus monkey

  G Kito, A Nishimura, T Susumu, R Nagata, Y Kuge, C Yokota, K Minematsu

  JOURNAL OF NEUROSCIENCE METHODS 105 (1) 45 - 53 0165-0270 2001/01 [Refereed][Not invited]
   

  To develop an experimental model of thromboembolic stroke without intracranial surgery, an autologous blood clot was delivered to the middle cerebral artery (MCA) via the internal carotid artery in cynomolgus monkeys. Male cynomolgus monkeys, in which a chronic catheter had been earlier implanted in the left interval carotid artery, were used. The clot was Bushed into the internal carotid artery under sevofluorane anesthesia. A neurologic deficit score was assigned after MCA embolization. After 24 h, cerebral infarct size and location were determined by the TTC staining method. Cerebral blood flow (CBF) was measured prior to and after MCA embolization, using positron emission tomography (PET). After embolization, long-lasting and profound extensor hypotonia of the contralateral upper and lower limbs, and mild to severe incoordination were observed. Contralateral hemiplegia was observed over the following 24 h. In gross morphologic observation of the brain, the lesions involved mostly the caudate nucleus, putamen, globus pallidus and insular cortex. CBF was maximally reduced in the left MCA territory, but not in the right MCA territory. This model is relevant to thromboembolic stroke in human in neurologic dysfunction and histopathologic brain damage. (C) 2001 Elsevier Science B.V. All rights reserved.
• Biodistribution of 3,4-dihydro-5-[C-11]methoxy-1(2H)-isoquinolinone, a potential PET tracer for poly(ADP-ribose) synthetase

  Y Miyake, Y Kuge, H Shimadzu, N Hashimoto, Y Ishida, M Shibakawa, T Nishimura

  NUCLEAR MEDICINE AND BIOLOGY 27 (8) 701 - 705 0969-8051 2000/11 [Refereed][Not invited]
   

  Poly(adenosine diphosphate-ribose) synthetase (PARS) is a nuclear enzyme that is activated by deoxyribonucleic acid (DNA) strand breaks and participates in DNA repair, Excessive PARS activation, however, leads to cell death due to depletion of adenosine triphosphate (ATP). To evaluate whether it is possible to detect excessive activation of PARS with positron emission tomography (PET), we examined the pharmacokinetics of 3,4-dihydro-5-[C-11]methoxy-1(2H)-isoquinolinone ([C-11]MIQO), a potent poly(ADP-ribose) synthetase inhibitor, in the brain of rats and monkeys. Although the uptake of [C-11]MIQO in the brain of normal rats was low, [C-11]MIRO was rapidly incorporated into and then quickly washed out from the brain. The uptake of the radiotracer in the brain of normal monkeys was also row; however, [C-11]MIQO gave a distribution image that differed from that of cerebral blood flow obtained by [O-15]water-PET. No localization of [C-11]MIQO in the brain of normal monkeys was observed. Low accumulation of some radioactivity was also observed in muscles surrounding the brain of monkeys, but did not seem to interfere with measurement of [C-11]MIQO uptake in the brain with PET. Thus, detection of [C-11]MIQO uptake with PET may be useful for detecting PARS activity in ischemic injury. NUCL MED BIOL 27;8:701-705, 2000. (C) 2000 Elsevier Science Inc. All rights reserved.
• [1-C-11]Octanoate as a PET tracer for studying ischemic stroke: Evaluation in a canine model of thromboembolic stroke with positron emission tomography

  Y Kuge, H Kawashima, K Minematsu, Y Hasegawa, T Yamaguchi, Y Miyake, T Hashimoto, M Imanishi, M Shiomi, N Tamaki, N Hashimoto

  BIOLOGICAL & PHARMACEUTICAL BULLETIN 23 (8) 984 - 988 0918-6158 2000/08 [Refereed][Not invited]
   

  Octanoate is taken up by the brain and converted in astrocytes to glutamine through the TCA cycle after beta-oxidatiun. Consequently, [1-C-11]octanoate might serve as a useful positron emission tomography (PET) probe for studying cerebral oxidative metabolism and/or astroglial functions. The present study attempted to evaluate the utility of using [1-C-11]octanoate as a PET tracer for imaging and evaluating the pathophysiology of ischemic stroke, We used a canine model of thromboembolic stroke. Five male beagle dogs were implanted with an indwelling catheter in the left internal carotid artery A single autologous blood clot was injected into the left internal carotid artery through the catheter, The brain distribution of [1-C-11]octanoate and cerebral blood Row (CBF) were determined 24 h after insult using a high resolution PET scanner Post mortem brain regions unstained with 2,3,5-triphenyltetrazolium chloride (TTC) were defined as infarcts. In the region of an infarct, accumulation of [1-C-11]octanoate decreased concurrently. with CBF reduction. In contrast, normal accumulation of [1-C-11]octanoate was observed in ischemic but vital regions, suggesting that an increased accumulation of [1-C-11]octanoate relative to CBF takes plate in these regions. In conclusion, [1-C-11]octanoate accumulated in ischemic hut vital regions, indicating that [1-C-11]octanoate is a potentially useful PET tracer for imaging and evaluating the pathophysiology of ischemic stroke.
• Effects of single and repetitive spreading depression on cerebral blood flow and glucose metabolism in cats: a PET study

  Y Kuge, Y Hasegawa, C Yokota, K Minematsu, N Hashimoto, Y Miyake, T Yamaguchi

  JOURNAL OF THE NEUROLOGICAL SCIENCES 176 (2) 114 - 123 0022-510X 2000/06 [Refereed][Not invited]
   

  To clarify the effects of spread depression (SD) on cerebral circulation and metabolism, we elicited a single or repetitive episode of and evaluated CBF and CMRglc three-dimensionally in normal cats (n = 4, in each group) using a high-resolution positron emission tomography (PET) scanner. SD was evoked by applying KCl to the left occipital cor-tex, We then monitored DC potential changes with tungsten electrodes inserted into the left temporal cortex. CBF was measured twice before and three times (immediately, 30-60 min, and 60-120 min) following KCl application using [O-15]H2O, and CMRglc was determined using 2-[F-18]fluoro-2-deoxy-D-glucose immediately following the last CBF measurement, The following results were obtained: (1) a single episode of SD produced a temporary: CBF increase. followed by a long-lasting hypoperfusion in the cortex with no significant changes to CBF observed in the subcortex; (2) no significant CMRglc changes were observed in either cortical or subcortical regions following a single episode of SD; (3) a flow-metabolism uncoupling was observed in the cortical regions concurrently with persistent hypoperfusion; (4) repetitive SD produced significant CBF changes in the cortex, and (5) the cortical CMRglc increased as a result of repeated episodes of SD, with no significant changes observed in the subcortex. Thus, we succeeded in determining three-dimensionally the effects of single and repetitive SD on CBF and CMRglc in cats using a high-resolution PET scanner. The present study provides the first direct evidence of CBF-CMglc uncoupling occurring concurrently with persistent hypoperfusion following SD. (C) 2000 Elsevier Science B.V. All rights reserved.
• Preliminary evaluation of [1-C-11]octanoate as a PET tracer for studying cerebral ischemia: A PET study in rat and canine models of focal cerebral ischemia

  Y Kuge, H Kawashima, T Hashimoto, M Imanishi, M Shiomi, K Minematsu, Y Hasegawa, T Yamaguchi, Y Miyake, N Hashimoto

  ANNALS OF NUCLEAR MEDICINE 14 (1) 69 - 74 0914-7187 2000/02 [Refereed][Not invited]
   

  Octanoate is taken up into the brain and is converted in astrocytes to glutamine through the TCA cycle after beta-oxidation. We speculate that [1-C-11]octanoate may be used as a tracer for astroglial functions and/or fatty acid metabolism in the brain and may be useful for studying cerebral ischemia. In the present study we investigated brain distribution of [1-C-11]octanoate and compared it with cerebral blood flow (CBF) by using rat and canine models of middle cerebral artery (MCA) occlusion and a high resolution PET. In rats brain distribution of [O-15]H2O measured 1-2 h and 5-6 h after insult was compared with that of [1-C-11]octanoate measured 3-4 h after insult. Radioactivity ratios of lesioned to normal hemispheres determined with [O-15]H2O were lower than those determined with [1-C-11]octanoate. These results were confirmed by a study on a canine model of MCA-occlusion. Twenty-four hours after insult, CBF decreased in the MCA-territory of the occluded hemisphere, whereas normal or higher accumulation of [1-C-11]octanoate was observed in the ischemic regions. The uptake of [1-C-11]octanoate-derived radioactivity therefore increased relative to CBF in the ischemic regions, indicating that [1-C-11]octanoate provides functional information different from CBF. In conclusion, we found that [1-C-11]octanoate is a potential radiopharmaceutical for studying the pathophysiology of cerebral ischemia.
• FDG MicroLabTMシステムを用いる18F-FDGの合成：臨床応用のための基礎的検討

  久下裕司, 塚本江利子, 加藤千恵次, 関興一, 大倉一枝, 大宮康明, 西嶋剣一, 田中明, 佐々木基仁, 玉木長良

  核医学 36 873 - 878 1999 [Refereed][Not invited]
  
• 全身FDG 検査における正常分布の検討

  加藤貴司, 塚本江利子, 杉並裕子, 高野晶寛, 馬淵恵, 吉永恵一郎, 志賀哲, 森田浩一, 加藤千恵次, 足立至, 久下裕司, 玉木長良

  核医学 36 971 - 977 1999 [Refereed][Not invited]
  
• Development of step-specific PET tracers for studying fatty acid beta-oxidation: Biodistribution of [1-C-11] octanoate analogs in rats and a cat

  H Kawashima, Y Kuge, K Yajima, Y Miyake, N Hashimoto

  NUCLEAR MEDICINE AND BIOLOGY 25 (6) 543 - 548 0969-8051 1998/08 [Refereed][Not invited]
   

  To evaluate the potential of [1-C-11]-3-(R,S)-methyloctanoate (BMOA), [1-C-11]-2-octynoate, and [1-C-11]-2-decynoate as PET tracers for studying particular steps in fatty acid beta-oxidation, we examined the pharmacokinetics of these compounds in rats and a cat. In rats given these compounds, high levels of radioactivity accumulated in the heart, liver, and kidneys, suggesting their potential as tracers for studying beta-oxidation in these tissues. These organs were clearly visible with PET in a cat given BMOA, indicating the utility of BMOA for imaging these organs. NUCL MED BIOL 25;6:543-548, 1998. (C) 1998 Elsevier Science Inc.
• 脳核医学診断用自動ROI設定システムの動物PET実験への応用

  久下裕司, 赤井信夫, 田村浩司, 山田学, 谷崎直昭, 橋本忠俊, 今西三明, 塩見美江, 石田良雄, 橋本直人

  核医学 35 733 - 740 1998 [Refereed][Not invited]
  
• Synthesis of [1-C-11]-2-octynoic acid, [1-C-11]-2-decynoic acid and [1-C-11]-3-(R,S)-methylocatanoic acid as potential markers for PET studies of fatty acid metabolism

  H Kawashima, K Yajima, Y Kuge, N Hashimoto, Y Miyake

  JOURNAL OF LABELLED COMPOUNDS & RADIOPHARMACEUTICALS 39 (3) 181 - 193 0362-4803 1997/03 [Refereed][Not invited]
   

  [1-C-11]-2-Octynoic acid, [1-C-11]-2-decynoic acid and [1-C-11]-3-(R,S)-methyloctanoic acid have been synthesized in order to evaluate these compounds as PET (Positron Emission Tomography) tracers for imaging in vivo medium-chain acyl-CoA dehydrogenase and medium-chain fatty acid utilization. The synthesis was performed by the Grignard reaction between alkylmagnesium bromides and [C-11]CO2. The radiochemical yields of [1-C-11]-2-octynoic acid, [1-C-11]-2-decynoic acid, and [1-C-11]-3-(R,S)-methyloctanoic acid were 10, 7 and 1% based on the [C-11]CO2 used respectively. Radiochemical purity was >99% in all cases.
• Positron emission tomography for quantitative determination of glucose metabolism in normal and ischemic brains in rats: An insoluble problem by the Harderian glands

  Y Kuge, K Minematsu, Y Hasegawa, T Yamaguchi, H Mori, H Matsuura, N Hashimoto, Y Miyake

  JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM 17 (1) 116 - 120 0271-678X 1997/01 [Refereed][Not invited]
   

  To examine the reliability of quantitative positron emission tomography studies in the rat (Rat-PET), we assessed the influence of radioactivity accumulated in the Harderian glands on PET CMR(glc) determination. We measured CMR(glc) by PET and ex vivo dissection methods by using 2-[F-18]fluoro-2-deoxy-D-glucose in rats with and without focal brain ischemia. The CMR(glc) values obtained by PET, after correcting with recovery coefficients, were higher than those measured by the ex vivo method at rostral slices, and reduction of the CMR(glc) in the ischemic brain was not demonstrated by PET in the frontal cortex, The radioactivity accumulated in the Harderian glands prevents the quantitative determination of CMR(glc) using Rat-PET.
• [1-11C]octanoate as a potential PET tracer for studying glial functions: PET evaluation in rats and cats

  Yuji Kuge, Hidefumi Kawashima, Shunji Yamazaki, Naoto Hashimoto, Yoshihiro Miyake

  Nuclear Medicine and Biology 23 (8) 1009 - 1012 0969-8051 1996/11 [Refereed][Not invited]
   

  To evaluate the ability of [1-11C]octanoate as a PET tracer for imaging the brain, we examined its distribution in the brain and surrounding tissues in rats and cats with PET. In rats, owing to the accumulated radioactivity in the harderian glands, clear brain images were not obtained at rostral levels. In cats, the brain was imaged clearly at every level of the coronal brain slices, suggesting the potential of [1-11C]octanoate for imaging the brain.
• [1-C-11]octanoate as a potential PET tracer for studying glial functions: PET evaluation in rats and cats

  Y Kuge, H Kawashima, S Yamazaki, N Hashimoto, Y Miyake

  NUCLEAR MEDICINE AND BIOLOGY 23 (8) 1009 - 1012 0883-2897 1996/11 [Refereed][Not invited]
   

  To evaluate the ability of [1-C-11]octanoate as a PET tracer for imaging the brain, we examined its distribution in the brain and surrounding tissues in rats and cats with PET. In rats, owing to the accumulated radioactivity in the harderian glands, clear brain images were not obtained at rostral levers. In cats, the brain was imaged clearly at every level of the coronal brain slices, suggesting the potential of [1-C-11]octanoate for imaging the brain. Copyright (C) 1996 Elsevier Science Inc.
• Uptake of radioactive octanoate in astrocytoma cells: Basic studies for application of [11C]octanoate as a PET tracer

  Shunji Yamazaki, Kiyoshi Fukui, Hidefumi Kawashima, Yuji Kuge, Yoshihiro Miyake, Kenji Kangawa

  Annals of Nuclear Medicine 10 (4) 395 - 399 0914-7187 1996 [Refereed][Not invited]
   

  Fatty acids are taken up and metabolized in the brain. In vitro uptake experiments on astrocytoma cells were carried out to assess the potential use of [1-11C]octanoate as a positron emission tomography (PET) tracer for astroglial functions. Uptake of [1-14C]octanoate increased in a time- dependent fashion until 60 min after application. The uptake of [1- 11C]octanoate showed similar results to that of [1-14C]octanoate until 10 min. As for medium pH, [1-14C]octanoate uptake increased gradually with the decrease in pH. We also examined the effects of glutamate, glucose deprivation and hypoxia on the uptake of octanoate and found that these conditions did not bring about any change in the extent of [1-14C]octanoate uptake. These results show that the octanoate uptake was not influenced by any of several pathological conditions. When the number of astrocytes increases in the area of hypoglycemia or hypoxia near a brain lesion, the amount of octanoate uptake also increases, so this indicates the possibility that 11C-octanoate will detect a brain lesion.
• NYLON MONOFILAMENT FOR INTRALUMINAL MIDDLE CEREBRAL-ARTERY OCCLUSION IN RATS

  Y KUGE, K MINEMATSU, T YAMAGUCHI, Y MIYAKE

  STROKE 26 (9) 1655 - 1657 0039-2499 1995/09 [Refereed][Not invited]
   

  Background and Purpose In rat middle cerebral artery (MCA) occlusion models with an intraluminal nylon monofilament, lesion volume and its reproducibility vary among laboratories. These variations may be caused by differences in the properties of nylon monofilaments. We performed the present study to compare the effects of two different types of 4-0 nylon monofilament on neurological and morphological outcomes in this model. Methods We randomly and blindly used two types of 4-0 nylon monofilament (Ethilon, n=15, and Nitcho, n=15) to permanently occlude the ostium of the right MCA intraluminally in rats. Neurological outcome and lesion size were compared 24 hours after MCA occlusion between the two groups. The diameter, tensile strength, and extensibility of each filament were measured. Results Neurological outcome was not different between the groups. The mortality within 24 hours was 13% (2/15) in the Ethilon group and 0% in the Nitcho group. Total lesion volume in the former was 295.9+/-97.2 mm(3) (mean+/-SD), significantly larger and more reproducible than that in the latter (190.3+/-144.7 mm(3), P=.026). The Ethilon filament had a significantly larger diameter (Ethilon, 0.193+/-0.001 mm; Nitcho, 0.180+/-0.001 mm; P<.0001), poorer tensile strength, and better extensibility than the other. Conclusions Exact diameter and quality are not always the same among nylon monofilaments, even if they meet the standard for the designation 4-0. The present study indicates that slight differences of filament characteristics significantly affect lesion volume and its reproducibility. This result may explain some conflicting observations in this MCA occlusion model.
• Brain uptake and metabolism of [1-11C]octanoate in rats: Pharmacokinetic basis for its application as a radiopharmaceutical for studying brain fatty acid metabolism

  Yuji Kuge, Kazuyoshi Yajima, Hidefumi Kawashima, Hiroyoshi Yamazaki, Naoto Hashimoto, Yoshihiro Miyake

  Annals of Nuclear Medicine 9 (3) 137 - 142 0914-7187 1995/09 [Refereed][Not invited]
   

  The uptake of octanoate in rat brain and its metabolism were investigated by means of intravenously injecting [1-11C] or [1-14C]octanoate as a tracer. The radioactivity in the cerebrum was increased by an injection of [1-11C]octanoate, and reached its peak level (0.33% ID/g) in about 2 to 5 min, and then decreased slowly. The cerebrum-to-blood ratio of the radioactivity increased with time over a period of 30 min. At 30 sec, [ 1-11C]octanoate that remained unchanged in the cerebrum accounted for only 8% of the total radioactivity, in spite of there being about 90% in the blood. By means of an injection of [ 1-14C]octanoate, more than 70% of the total radioactivity in the cerebrum was found to be attributable to radiolabeled glutamate and glutamine at each time point measured between 30 sec and 30 min. The results show that [1-11C]octanoate enters rat brain easily and is trapped in the cerebrum, probably in the form of glutamate and glutamine, and the usefulness of [ 1-11C] octanoate as a radiopharmaceutical for studying brain fatty acid metabolism by positron emission tomography is therefore suggested. © 1995 Springer-Verlag.
• OPTIMAL FORMULATION OF AN ANGIOGENESIS INHIBITOR, TNP-470, FOR ARTERIAL INJECTION DETERMINED BY IN-VITRO DRUG-RELEASE AND STABILITY, AND IN-VIVO ANTITUMOR-ACTIVITY

  S YANAI, H OKADA, K SAITO, Y KUGE, Y OGAWA, H TOGUCHI

  INTERNATIONAL JOURNAL OF PHARMACEUTICS 123 (2) 237 - 245 0378-5173 1995/09 [Refereed][Not invited]
   

  TNP-470 (6-O-(N-chloroacetylcarbamoyl)fumagillol AGM-1470) is an angiogenesis inhibitor, a new type of anticancer drug which prevents tumor neovascularization, thereby blocking the nutrient supply to tumors. In this study, we sought the optimal formulation of TNP-470 for arterial injection in order to achieve strong anticancer activity due to the tumor-selective targeting of the drug, by investigating in vitro release and stability and in vivo rabbit VX-2 antitumor activity. We found that a medium-chain triglyceride (MCT) solution containing TNP-470 facilitated the 2-week sustained release of TNP-470 in vitro and fairly good long-term stability of the agent, although it was very labile in aqueous solution. In a rabbit VX-2 tumor model, 3 weeks after inoculation on the inner side of the leg, the antitumor activities of various formulations of TNP-470 were evaluated by administration into the femoral artery feeding the tumor. Compared with Lipiodol solution or PLGA microspheres containing TNP-470, the MCT solution containing TNP-470 exerted stronger and more persistent antitumor activity accompanied by tumor regression for 3 weeks subsequently. The release sustainability of TNP-470 in the in vitro release test was suggested to be an important factor in the antitumor activity of each formulation. From these results, we conclude that the MCT solution is the most promising formulation of TNP-470 as an arterial injection for treatment of cancers.
• ANTITUMOR EFFECT OF ARTERIAL ADMINISTRATION OF A MEDIUM-CHAIN TRIGLYCERIDE SOLUTION OF AN ANGIOGENESIS INHIBITOR, TNP-470, IN RABBITS BEARING VX-2 CARCINOMA

  S YANAI, H OKADA, K SAITO, Y KUGE, M MISAKI, Y OGAWA, H TOGUCHI

  PHARMACEUTICAL RESEARCH 12 (5) 653 - 657 0724-8741 1995/05 [Refereed][Not invited]
   

  Using rabbits bearing VX-2 carcinoma on the inner side of the leg, we examined the antitumor activity of a medium-chain triglyceride (MCT) solution of an angiogenesis inhibitor, TNP-470 (AGM-1470, 6-O-(N-chloroacetylcarbamoyl)-fumagillol, following administration into the femoral artery feeding the tumor, The MCT solution of TNP-470 (1 and 5 mg) strongly suppressed tumor growth following a single intra-arterial (i. a.) injection 2 or 3 weeks after tumor inoculation. Moreover, remarkable regression of well-developed tumors, those 4 weeks after inoculation, was obtained by i. a. injection of the MCT solution containing 20 mg of TNP-470 without any influence on body weight. The antitumor effects were potentiated by coadministration of doxorubicin or mitomycin C (MMC) in the solution or microspheres containing MMC. In a shell-less chorioallantoic membrane (CAM) assay, angiogenesis was inhibited when a droplet of the MCT solution containing 25 mu g of TNP-470 was placed on the CAM for 2 days, suggesting that the prolonged antitumor effect resulted from the inhibition of tumor neovascularization by sustained drug release from the preparation. These results indicate that i. a. injection of the MCT solution of TNP-470 is promising for treating well-developed tumors.
• ANTITUMOR-ACTIVITY OF A MEDIUM-CHAIN TRIGLYCERIDE SOLUTION OF THE ANGIOGENESIS INHIBITOR TNP-470 (AGM-1470) WHEN ADMINISTERED VIA THE HEPATIC-ARTERY TO RATS BEARING WALKER-256 CARCINOSARCOMA IN THE LIVER

  S YANAI, H OKADA, M MISAKI, K SAITO, Y KUGE, Y OGAWA, H TOGUCHI

  JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS 271 (3) 1267 - 1273 0022-3565 1994/12 [Refereed][Not invited]
   

  The antitumor effect of an angiogenesis inhibitor, TNP-470 (AGM-1470, 6-0-(N-chloroacetylcarbamoyl)-fumagillol), administered via the hepatic artery in a medium-chain triglyceride (MCT) solution, in which TNP-470 is very stable, was examined in rats bearing Walker 256 carcinosarcoma in the liver. The MCT solution containing 0.1 mg of TNP-470 completely suppressed tumor growth after a single arterial injection, and the solutions containing 0.5 similar to 5 mg of TNP-470 caused tumor regression without severe side effects on body weight gain or liver function. These antitumor effects lasted for at least 2 weeks. Moreover, the administration of the MCT solution containing 5 mg of TNP-470 also caused remarkable regression of well-developed enlarged tumors 2 weeks after inoculation, indicating potential in the treatment of unresectable hepatic cancer. When the MCT solution containing radiolabeled TNP-470 was injected via the hepatic artery, the initial radioactivity in the tumor was 22 times that in the normal part of the liver and 5.7 times that in the tumor when an aqueous solution of radiolabeled TNP-470 was injected. Also, in the case of the MCT solution, the radioactivity in the tumor was maintained at a relatively high level for over 2 weeks after injection. These results indicate that the remarkable antitumor effect resulted from the selective delivery and prolonged retention of TNP-470 at the tumor site.
• ACCUMULATION OF RADIOACTIVITY IN THE PANCREAS AFTER INTRAVENOUS ADMINISTRATION OF [N-13] AMMONIA

  H SAJI, Y KUGE, K YAMAMOTO, Y MAGATA, Y YONEKURA, J KONISHI, A YOKOYAMA

  NUCLEAR MEDICINE AND BIOLOGY 19 (5) 531 - & 0883-2897 1992/07 [Refereed][Not invited]
   

  A biodistribution study of [N-13]ammonia in rats showed a high accumulation of radioactivity in the pancreas soon after the intravenous injection of this tracer. In humans, the pancreas was also clearly visualized by dynamic positron emission tomography soon after the intravenous injection of [N-13]ammonia. To investigate the mechanism of the pancreatic accumulation of [N-13]ammonia. in vitro studies with pancreatic slices and in vivo biodistribution and metabolism studies were carried out in rats. The results indicated that [N-13]ammonia enters the pancreas from the blood by diffusion at a rate dependent on local blood flow, and then is rapidly incorporated into the amino acid fraction (mainly the glutamine fraction), followed by its incorporation into protein. These findings suggest that [N-13]ammonia could be useful for diagnostic imaging of the pancreas.
• INVESTIGATION OF RADIOPHARMACEUTICALS FOR PANCREATIC IMAGING - ACCUMULATION OF AMINES IN THE PANCREAS

  H SAJI, Y KUGE, Y MAGATA, Y FUJIBAYASHI, A YOKOYAMA

  CHEMICAL & PHARMACEUTICAL BULLETIN 40 (1) 161 - 164 0009-2363 1992/01 [Refereed][Not invited]
   

  To develop radiopharmaceuticals for pancreatic imaging, radioiodinated ethyl benzene derivatives containing various functional groups (amino, carboxyl, and methyl groups) were synthesized and the effects of these functional groups were compared in vitro and in vivo. At 2 min after intravenous injection, the amino derivative, 2-(4-iodophenyl)-N,N-dimethyl ethylamine, displayed about twice the pancreatic uptake and a more than 8-fold higher pancreas/liver ratio than the carboxyl and methyl derivatives. This high and selective in vivo accumulation on the amino derivative in the pancreas was well supported by in vitro studies on the uptake by pancreatic tissue slices. The mechanism promoting pancreatic accumulation of radiopharmaceuticals with an amino group is also discussed.
• Accumulation and metabolism of [125I] HIPDM in the rat pancreas

  Hideo Saji, Yuji Kuge, Daisuke Tsutsumi, Kazutaka Yamamoto, Junji Konishi, Akira Yokoyama

  Annals of Nuclear Medicine 5 (4) 157 - 161 0914-7187 1991/12 [Refereed][Not invited]
   

  Our previous studies have shown a high accumulation of [125I]N,N,N′-trimethyl-N′-(2-hydroxy-3-methyl-5-iodobenzyl)-l,3-propanediamine (HIPDM) in the human pancreas. In this study, the pancreatic accumulation and metabolism of [125I]HIPDM were studied in rats to determine the factors influencing its uptake by this organ. In biodistribution studies, [125I]HIPDM showed a high uptake by the pancreas similar to that by the brain and lungs, both organs with a low tissue pH. TLC analysis of pancreatic homogenate after the injection of [125I]HIPDM showed that it was metabolically stable in this organ. Moreover, in the pancreatic homogenate, the bulk of the radioactivity was recovered from the microsomal fraction, and the radioactivity bound to microsomal particles showed release that was dependent on the Ca2+ or Mg2+ concentration in the incubation medium. These results suggest that the initial pancreatic uptake of [125I]HIPDM may be a function of blood flow and governed by the pH gradient hypothesis, while subsequent retention may occur secondary to ionic binding within the pancreas. © 1991 Springer-Verlag.
• 新規カルシウム拮抗薬 Manidipine Hydrochloride [CV-4093(2HCl)]のラット、イヌにおける代謝

  吉田清志, 三谷政義, 塚本剛司, 久下裕司, 小林卓郎, 棚山薫晴

  薬理と治療 17 2119 - 2135 1989 [Not refereed][Not invited]
  
• 遺伝子組換え型ヒトインターロイキン-2 (TGP-3) のラット、マウス、ウサギ、イヌ、サルにおける薬物動態

  小林卓郎, 久下裕司, 朴木英明, 飯沢祐史, 山本仁, 石古博昭, 棚山薫晴

  基礎と臨床 23 4309 - 4325 1989 [Not refereed][Not invited]
  
• INVIVO EVALUATION OF RADIOIODINATED SPIROPERIDOL DERIVATIVES AS RADIOPHARMACEUTICAL FOR DOPAMINE RECEPTOR STUDY

  H SAJI, T TOKUI, A SAIGA, Y KUGE, NAKATSUKA, I, M OKUNO, A YOSHITAKE, K TORIZUKA, A YOKOYAMA

  JOURNAL OF LABELLED COMPOUNDS & RADIOPHARMACEUTICALS 23 (10-12) 1323 - 1324 0362-4803 1986/10 [Refereed][Not invited]
  

MISC

• PSMA-PET ～PETによる最新の前立腺癌診断法～

  久下裕司, 志賀 哲, 水野雄貴, 平田健司  Isotope News  774-  18  -21  2021/04
• Clinical practice guidelines for high-resolution breast PET, 2019 edition

  Yoko Satoh, Masami Kawamoto, Kazunori Kubota, Koji Murakami, Makoto Hosono, Michio Senda, Masayuki Sasaki, Toshimitsu Momose, Kengo Ito, Terue Okamura, Keiichi Oda, Yuji Kuge, Minoru Sakurai, Ukihide Tateishi, Yasuhisa Fujibayashi, Yasuhiro Magata, Takeshi Yoshida, Atsuo Waki, Katsuhiko Kato, Teisuke Hashimoto, Mayuki Uchiyama, Seigo Kinuya, Tatsuya Higashi, Yasuhiro Magata, Akihiro Machitori, Hirotaka Maruno, Ryogo Minamimoto, Keiichiro Yoshinaga  Annals of Nuclear Medicine  35-  (3)  406  -414  2021/03  [Refereed][Invited]
   

  Breast positron emission tomography (PET) has had insurance coverage when performed with conventional whole-body PET in Japan since 2013. Together with whole-body PET, accurate examination of breast cancer and diagnosis of metastatic disease are possible, and are expected to contribute significantly to its treatment planning. To facilitate a safer, smoother, and more appropriate examination, the Japanese Society of Nuclear Medicine published the first edition of practice guidelines for high-resolution breast PET in 2013. Subsequently, new types of breast PET have been developed and their clinical usefulness clarified. Therefore, the guidelines for breast PET were revised in 2019. This article updates readers as to what is new in the second edition. This edition supports two different types of breast PET depending on the placement of the detector: the opposite-type (positron emission mammography; PEM) and the ring-shaped type (dedicated breast PET; dbPET), providing an overview of these scanners and appropriate imaging methods, their clinical applications, and future prospects. The name “dedicated breast PET” from the first edition is widely used to refer to ring-shaped type breast PET. In this edition, “breast PET” has been defined as a term that refers to both opposite- and ring-shaped devices. Up-to-date breast PET practice guidelines would help provide useful information for evidence-based breast imaging.
• Investigation of changes in tumor environment after photoimmunotherapy with［18F］FDG and ［18F］FMISO

  中島孝平, 杉川晃代, 安井 博宣, 東川桂, 高倉栄男, 志賀哲, 久下裕司, 小川美香子  JSMI Report  13-  (1)  17  -22  2020/01  [Refereed][Invited]
  
• The Roles of Hypoxia Imaging Using 18F-Fluoromisonidazole Positron Emission Tomography in Glioma Treatment.

  Kenji Hirata, Shigeru Yamaguchi, Tohru Shiga, Yuji Kuge, Nagara Tamaki  Journal of clinical medicine  8-  (8)  E1088  2019/07/24  [Refereed][Invited]
   

  Glioma is the most common malignant brain tumor. Hypoxia is closely related to the malignancy of gliomas, and positron emission tomography (PET) can noninvasively visualize the degree and the expansion of hypoxia. Currently, 18F-fluoromisonidazole (FMISO) is the most common radiotracer for hypoxia imaging. The clinical usefulness of FMISO PET has been established; it can distinguish glioblastomas from lower-grade gliomas and can predict the microenvironment of a tumor, including necrosis, vascularization, and permeability. FMISO PET provides prognostic information, including survival and treatment response information. Because hypoxia decreases a tumor's sensitivity to radiation therapy, dose escalation to an FMISO-positive volume is an attractive strategy. Although this idea is not new, an insufficient amount of evidence has been obtained regarding this concept. New tracers for hypoxia imaging such as 18F-DiFA are being tested. In the future, hypoxia imaging will play an important role in glioma management.
• 放射性医薬品の取扱に関するアンケート調査報告。

  日本核医学会, 核医学領域における薬剤師の在り方検討委員会, 久下裕司, 桒原健, 小泉潔, 鈴木貴明, 藤塚一行, 間賀田泰寛, 八島秀明, 放射性医薬品取り扱いガイドライン講習会ワーキンググループ委員, 荒野泰, 岡沢秀彦, 小川清, 小野欽也, 片渕哲朗, 川井恵一, 倉橋達人, 小池克美, 小泉潔, 中川貴之, 藤塚一行, 間賀田泰寛  核医学  56-  25  -31  2019  [Not refereed][Not invited]
  
• Imaging modalities for drug-related osteonecrosis of the jaw (3), Positron emission tomography imaging for the diagnosis of medication-related osteonecrosis of the jaw.

  Kitagawa Y, Ohga N, Asaka T, Sato J, Hata H, Helman J, Tsuboi K, Amizuka N, Kuge Y, Shiga T  Jpn Dent Sci Rev.  55-  (1)  65  -67  2019  [Not refereed][Invited]
   

  Medication-related osteonecrosis of jaws (MRONJ) is one of the most complicated inflammatory conditions in oral and maxillofacial region. It is very difficult to correctly evaluate the degree and extent of necrosis and infection. This refractory osteonecrosis often needs extended surgery, leading to impaired quality-of-life. We have performed hyperbaric oxygen therapy (HBO) combined with conservative surgery for advanced cases. We have appraised the value of FDG-PET and 3-phase bone scintigraphy in the diagnosis and management of this condition. MRONJ showed significantly higher SUVmax on FDG-PET than the others. Although the 3 phase pool bone images did not change significantly, perfusion and static bone image as well as PET showed remarkable response to HBO for MRONJ. SUVmax after HBO was significantly lower than those of before HBO. These preliminary results indicate that FDG-PET is useful for monitoring the effect of HBO for MRONJ.
• FDG PET、PET/CT診療ガイドライン2018

  細野 眞, 千田 道雄, 佐々木 雅之, 百瀬 敏光, 伊藤 健吾, 岡村 光英, 織田 圭一, 川本 雅美, 久下 裕司, 櫻井 実, 立石 宇貴秀, 藤林 康久, 間賀田 泰寛, 村上 康二, 吉田 毅, 脇 厚生, 加藤 克彦, 橋本 禎介, 内山 眞幸, 絹谷 清剛, 東 達也, 待鳥 詔洋, 丸野 廣大, 南本 亮吾, 吉永 恵一郎, 日本核医学会, PET核医学委員会, 健保委員会  核医学  55-  (1)  1  -22  2018/12
• Nuclear Medicine Today 2018 最新トピックスから探る核医学の現在と未来 ?Theranosticsに向けた研究開発の最新トピックス 5．68Ge/68Gaジェネレータを用いるPET薬剤の研究開発と将来展望。

  久下裕司, 東川 桂, 岡本祥三, 志賀 哲  INNERVISION  33-  (11)  58  -61  2018  [Not refereed][Invited]
  
• Nuclear Medicine Today 2018 最新トピックスから探る核医学の現在と未来 ?Theranosticsに向けた研究開発の最新トピックス 4．前立腺がんに対するPSMA-PETとPSMAによるアイソトープ治療の最新動向。

  岡本祥三, 志賀 哲, 久下裕司  INNERVISION  33-  (11)  55  -57  2018  [Not refereed][Invited]
  
• 口腔癌における低酸素分子イメージング

  北川善政, 佐藤 淳, 大賀則孝, 浅香卓哉, 竹内康人, 犬伏正幸, 久下裕司, 志賀 哲  お茶の水醫學雑誌  66-  (2)  193  -211  2018  [Not refereed][Invited]
   

  低酸素状態(hypoxia)は固形癌の重要な予後因子の一つで、放射線・化学療法に抵抗性を示し、侵襲性や増殖能が旺盛になることが報告されている。犬伏らは、Na+/I-共輸送蛋白(NIS:sodium/iodine symporter)レポーター遺伝子を利用して、虚血性心疾患において遺伝子発現の画像化に成功した。この手法を発展させ、癌細胞の治療抵抗性に関与するHIF-1/HREによる低酸素遺伝子応答のイメージングを試みた。HIF-1/HREによる低酸素遺伝子応答によってNISを発現する癌細胞株を樹立し、PET(124/I-)あるいはSPECT(99mTcO4-)イメージングに成功した。低酸素PETトレーサーの腫瘍集積値は、治療抵抗性との強い関係性を示唆しており、予後因子として利用できることの裏付けとなる結果であった。北大病院では2009年から核医学診療科の協力のもと、18F-Fluorodeoxyglucose(FDG)PETとともに、低酸素分子イメージングとして18F-fluoromisonidazole(FMISO)PETを口腔扁平上皮癌(OSCC)患者に臨床応用している。われわれは、OSCCにおけるFMISO-PETの集積と組織中のHIF-1αの発現が有意に関連していることを世界ではじめて明らかにした。さらに術前化学療法の効果の予測、増殖能との関係、低酸素容積(hypoxic volume:HV)と予後との関連も見出した。FIMISO-PETは癌診療に有望な低酸素分子イメージングである。(著者抄録)
• 特集 薬剤関連顎骨壊死の画像診断up to date。 薬剤関連顎骨壊死のPET検査。

  北川 善政, 浅香 卓哉, 佐藤 淳, 秦 浩信, 坪井 香奈子, 網塚 憲生, 久下 裕司, 志賀 哲  臨床放射線  63-  (10)  1071  -1081  2018  [Not refereed][Invited]
  
• Recent Advances in the Development of PET/SPECT Probes for Atherosclerosis Imaging

  Yoichi Shimizu, Yuji Kuge  Nuclear Medicine and Molecular Imaging  50-  (4)  284  -291  2016/12/01  [Refereed][Invited]
   

  The rupture of vulnerable atherosclerotic plaques and subsequent thrombus formation are the major causes of myocardial and cerebral infarction. Accordingly, the detection of vulnerable plaques is important for risk stratification and to provide appropriate treatment. Inflammation imaging using 2-deoxy-2-[18F]fluoro-D-glucose (18F-FDG) has been most extensively studied for detecting vulnerable atherosclerotic plaques. It is of great importance to develop PET/SPECT probes capable of specifically visualizing the biological molecules involved in atherosclerotic plaque formation and/or progression. In this article, we review recent advances in the development of PET/SPECT probes for visualizing atherosclerotic plaques and their application to therapy monitoring, mainly focusing on experimental studies.
• イメージングによる“がん”の治療効果予測−新規核医学診断薬（[123I]IIMU）の臨床研究への歩み−

  久下裕司, 西嶋剣一, 大倉一枝, 志賀 哲, 玉木長良  ISOTOPE NEWS  729-  16  -20  2015  [Not refereed][Invited]
  
• 新しいがんの放射線生物学を拓くイメージング技術

  安井 博宣, 戒田 篤志, 兵藤 文紀, 三浦 大典, 久下 裕司, 松本 孔貴  放射線生物研究  49-  (3)  263  -283  2014/09  [Not refereed][Invited]
   

  がんの放射線感受性を規定する因子は細胞周期、低酸素、エネルギー代謝、レドックスなど多岐に渡っている上に、腫瘍組織内の不均一性がその理解を一層難しいものとしている。がん微小環境と呼ばれるこの特性はがんの進行や治療応答に対し刻々と変化するため、既存の病理固定組織によるスナップショット的な空間情報では統合的に捉え難い。しかしながら、近年の工学、薬学ならびに遺伝子工学領域の発展により、非侵襲的な生体機能の画像化を高分解能で行うことが可能となってきている。さらにや上記に述べた放射線感受性因子の各々に特化した経時的解析も確立されつつあり、新たながん治療開発への道標になりうるものと期待される。本稿では、電子スピンや核スピンに対する磁気共鳴イメージング法、in situ質量分析イメージング法、リアルタイム細胞周期蛍光イメージング法ならびに核医学イメージング法といった先進的画像化技術について概説し、これら手法を用いた複雑ながん微小環境の解明と放射線治療戦略の近未来の展望について考察する。(著者抄録)
• Concepts about rebuilding of a radiation facility

  NOYA Yoichi, ABO Norifumi, SHIMIZU Yoichi, KUBO Naoki, KUGE Yuji  Japanese Journal of Radiation Safety Management  13-  (1)  51  -54  2014  [Not refereed][Invited]
   

  In this report, we introduced our project of the extension and the rebuilding of the building of Central Institute of Isotope Science (CIS), Hokkaido University, which has been planned in terms of the present state and the future outlook for the management of CIS. We first fixed a layout of that building and the dose of radioisotope (RI) in the renewed CIS building in consideration of the present usage states, and then carried out a sort of designing of building such as calculation of the wall thickness corresponded to the RI usage dose, arrangement of exhaust and drainage equipments, and so on. Furthermore, we attempted to design the building with an appropriate function for education and safety control of radiation and RI as well as flexibility in response to user's demands on performing a various kind of researches.
• イメージング質量分析を用いたスフィンゴミエリンの組織内分布と制御機構の解明

  杉本正志, 志水陽一, 五十嵐靖之, 久下裕司  JSMI Report  9-  (1)  43  -45  2014  [Not refereed][Invited]
  
• 核医学による代謝の空間的，定量的評価

  久下裕司  血栓止血誌  25-  (3)  363  -370  2014  [Not refereed][Invited]
  
• Molecular Imaging 2014 分子イメージングはどこまで進んだか ?分子イメージングの最新動向 １．核医学における分子イメージングの最新動向 5)製造標準化の現状と展望

  脇厚生, 久下裕司, 西嶋剣一, 藤林靖久  INNERVISION  29-  (7)  23  -26  2014  [Not refereed][Invited]
  
• A new horizon of nuclear medicine : Application to treatment strategy of cancer

  久下 裕司, 趙 松吉, 志賀 哲  放射線生物研究  48-  (4)  353  -363  2013/12
• 特集 心臓病における核医学検査の進歩 循環器領域の放射性薬剤の進歩

  久下裕司  呼吸と循環  61-  (11)  1001  -1007  2013  [Not refereed][Invited]
  
• 特集 心血管イメージング最前線−エコー, CTからcoronary imagingまで−５．核医学検査 f. 分子イメージングの方向性

  久下裕司, 玉木長良  Heart View  17-  (12(増刊号))  320  -325  2013  [Not refereed][Invited]
  
• 特集 「百聞は一見にしかず 生体イメージングがもたらす診断と治療の戦略」セミナー 循環器領域の分子イメージング

  久下裕司, 玉木長良  ファルマシア  49-  (7)  682  -687  2013  [Not refereed][Invited]
  
• 特集 不安定プラークの病態と診断 10.不安定プラークと分子イメージング

  久下裕司, 玉木長良  月刊循環器  3-  (1)  69  -77  2013  [Not refereed][Invited]
  
• Molecular imaging in heart failure patients

  Tamaki N, Kuge Y, Yoshinaga K  Clin Transl Imaging  1-  (5)  341  -354  2013  [Not refereed][Invited]
  
• Bone marrow stromal cell transplantation enhances recovery of local glucose metabolism after cerebral infarct in rats : A serial [18]F-FDG PET study

  宮本 倫行, 黒田 敏, 趙 松吉, 孫田 恵一, 伊東 雅基, 川堀 真人, 七戸 秀夫, 宝金 清博, 久下 裕司, 玉木 長良  北海道醫學雜誌 = Acta medica Hokkaidonensia  87-  (6)  269  -269  2012/11/01  [Not refereed][Not invited]
  
• 特集１ 心臓核医学の最先端 1．動脈硬化イメージング−実験的検討

  久下裕司, 趙 芫, 趙 松吉, 玉木長良  ＰＥＴジャーナル  18-  14  -16  2012  [Not refereed][Invited]
  
• 医薬品開発（又は創薬・育薬）における分子イメージング技術の現状と進歩

  久下裕司, 西嶋剣一, 孫田恵一, 趙 松吉, 玉木長良  医薬品医療機器レギュラトリーサイエンス  43-  (4)  308  -313  2012  [Not refereed][Invited]
  
• 交感神経と循環器疾患 交感神経イメージング

  玉木長良, 吉永恵一郎, 久下裕司  Cardiac Practice  23-  (2)  143  -147  2012  [Not refereed][Invited]
  
• 特集 冠動脈疾患の診断・治療における画像診断の進歩 分子イメージングによる冠動脈病変評価

  玉木長良, 吉永恵一郎, 久下裕司  Cardiac Practice  23-  (1)  23  -27  2012  [Not refereed][Invited]
  
• 動脈硬化プラーク評価における分子イメージングの有用性と展望 (特集 MDCT・MRI・SPECT・PETをいかに使い分けるか) -- (CTによる冠動脈狭窄評価能--最新のエビデンスと臨床適応)

  玉木 長良, 久下 裕司  心CT  35  -40  2011/03  [Not refereed][Not invited]
  
• 特集１ 次世代腫瘍分子イメージング ４．アポトーシスイメージングプローブ

  久下裕司, 竹井俊樹, 趙 松吉  ＰＥＴジャーナル  13-  23  -25  2011  [Not refereed][Invited]
  
• 特集１ 核医学検査の新しい展開〜治療戦略への応用 治療戦略に役立つ放射性薬剤の開発

  久下裕司, 西嶋剣一, 趙 松吉  映像情報メディカル  43-  (11)  842  -849  2011  [Not refereed][Invited]
  
• 心不全の分子イメージング

  玉木長良, 吉永恵一郎, 久下裕司  日本心不全学会 News Letter  15-  (2)  8  -9  2011  [Not refereed][Invited]
  
• SPECT、PETによるプラークイメージング

  玉木長良, 趙 芫, 久下裕司  動脈硬化予防  9-  (2)  53  -57  2010  [Not refereed][Invited]
  
• Molecular Imaging of Apoptosis with Radio-Labeled Annexin A5 Focused on the Evaluation of Tumor Response to Chemotherapy

  Yuji Kuge, Songji Zhao, Toshiki Takei, Nagara Tamaki  ANTI-CANCER AGENTS IN MEDICINAL CHEMISTRY  9-  (9)  1003  -1011  2009/11  [Refereed][Invited]
   

  Apoptosis, or programmed cell death, is activated in the course of successful anti-neoplastic therapy. Determining baseline levels of apoptosis and the increment of apoptosis induced by therapy can serve as useful prognostic markers. Thus, non-invasive assessment of apoptosis would be desirable to provide clinicians with information on therapeutic efficacy as well as for the development and testing of new anticancer drugs. In these regards, apoptosis detecting radio-probes (radiopharmaceuticals) have been extensively studied. Annexin A5 (annexin V) is an endogenous protein that binds with high affinity and specificity to phosphatidylserine, which is presented on the cell surface in an early process of apoptosis. Accordingly, apoptotic cells can be detected in vivo using annexin A5 labeled with radionuclides, such as (99m)Tc and (18)F. To date, several annexin A5 radio-probes have been developed. Among these, (99m)Tc-HYNIC-annexin A5 is the best candidate for apoptosis imaging. The apoptosis imaging using radio-labeled annexin A5 has been applied for detecting apoptosis in vivo in the experimental and clinical evaluation of the tumor response to chemotherapy or radiotherapy. The present review describes apoptosis imaging with annexin A5 radio-probes, focusing on its application to the evaluation of the tumor response to chemotherapy. First, principles of apoptosis imaging with annexin A5 radio-probes are described. Next, experimental results with radio-labeled annexin A5 in the evaluation of therapeutic efficacy are discussed. Finally, clinical application of apoptosis imaging with radio-labeled annexin A5 is addressed.
• PET核医学検査による評価

  玉木長良, 趙 芫, 久下裕司, 志賀哲  Mebio  26-  (4)  114  -118  2009  [Not refereed][Invited]
  
• 核医学の軌跡(PETを中心に)

  玉木長良, 吉永恵一郎, 久下裕司  DIGITALMEDICINE  42-  26  -29  2009  [Not refereed][Invited]
  
• Myocardial metabolic imaging in the clinical setting

  Tamaki N, Kuge Y, Yoshinaga K  Eur Cardiolgy  5-  (1)  15  -18  2009  [Not refereed][Invited]
  
• 放射線治療を指向したPET/SPECTプローブの開発〜低酸素イメージングを中心に〜

  久下裕司, 上田真史, 趙 松吉, 工藤 喬, 近藤科江, 田中正太郎, 玉木長良, 平岡眞寛, 佐治英郎  癌の臨床  54-  (2)  105  -108  2008  [Not refereed][Invited]
  
• 分子イメージングとがん治療戦略：イメージングによるインビボ組織染色を目指して

  久下裕司, 佐治英郎, 玉木長良, 趙松吉, 関興一, 上田真史, 清野泰  INNERVISION  22-  (7)  42  2007  [Not refereed][Invited]
  
• 心受容体イメージング

  玉木長良, 塚本隆裕, 犬伏正幸, 久下裕司  日本臨床  65-  (2)  303  -307  2007  [Not refereed][Invited]
  
• PETの展望 「新しいPET用薬剤」

  久下裕司, 西嶋剣一  Pharma Medica  24-  (10)  51  -54  2006  [Not refereed][Invited]
  
• 動脈硬化病態の解析と分子イメージング：プロスタグランジン合成酵素を標的として

  久下裕司, 佐治英郎, 清野泰, 横田千晶, 玉木長良, 関興一  INNERVISION  21-  (7)  17  2006  [Not refereed][Invited]
  
• 動脈硬化の質的診断のための分子イメージング

  佐治英郎, 久下裕司, 向高弘, 多田村栄二, 久米典昭, 野原隆司  INNERVISION  21-  (7)  27  2006  [Not refereed][Invited]
  
• “訪問”日本メジフィジックス株式会社 PETラボ（京都ラボ）

  久下裕司  Isotope News  607-  10  -13  2004  [Not refereed][Invited]
  
• ミニガンマカメラの基礎実験及び臨床への応用の可能性

  佐治英郎, 清野 泰, 久下裕司  Isotope News  606-  2  -6  2004  [Not refereed][Invited]
  
• 核医学的手法を用いた動脈硬化巣の画像化の可能性

  玉木長良, 森田浩一, 竹井俊樹, 久下裕司  呼吸と循環  52-  (7)  703  -707  2004  [Not refereed][Invited]
  
• 特集“再生医療と画像診断 −失われた機能の再生をめざして−” 遺伝子治療における画像診断

  久下 裕司, 佐治英郎, 清野 泰  映像情報メディカル  36-  (8)  856  -860  2004  [Not refereed][Invited]
  
• PETとレセプター 〜脳と心筋のレセプター機能解析〜

  久下 裕司, 玉木 長良, 佐治 英郎  医薬ジャーナル  40-  (5)  1451  -1457  2004  [Not refereed][Invited]
  
• Invited commentary - What is the clinical role of neuronal imaging?

  K Morita, Y Kuge, N Tamaki  JOURNAL OF NUCLEAR MEDICINE  44-  (9)  1467  -1468  2003/09  [Not refereed][Invited]
  
• 受容体イメージング

  玉木長良, 志賀 哲, 久下裕司  Medical Imaging Technology  21-  (5)  344  -349  2003  [Not refereed][Invited]
  
• FDG-PET検査の改良による腫瘍の鑑別診断法の開発：膜輸送遺伝子による検討

  玉木長良, 久下裕司, 趙 松吉, 塚本江利子, 中駄邦博  INNERVISION  18-  (8)  25  2003  [Not refereed][Invited]
  
• 使い捨てFDG合成キット：MicroLab

  久下裕司, 西嶋剣一, 玉木長良  RADIOISOTOPES  51-  191  -195  2002  [Not refereed][Invited]
  
• Current status and future of metabolic cardiac imaging

  N Tamaki, Y Kuge, C Katoh  NUCLEAR MEDICINE COMMUNICATIONS  22-  (8)  847  -850  2001/08  [Not refereed][Invited]
  
• The road to quantitation of regional myocardial uptake of tracer

  N Tamaki, Y Kuge, E Tsukamoto  JOURNAL OF NUCLEAR MEDICINE  42-  (5)  780  -781  2001/05  [Not refereed][Invited]
  
• 院内製造されたFDGを用いてPET検査を行うためのガイドライン : 日本核医学会

  福田 寛, 玉木 長良, 畑澤 順, 井戸 達雄, 遠藤 啓吾, 御前 隆, 石田 良雄, 越智 宏暢, 米倉 義晴, 桑原 康雄, 鳥塚 莞爾, 小西 淳二, 古賀 佑彦, 西村 恒彦, 伊藤 健吾, 岩田 錬, 宇野 公一, 前田 稔, 窪田 和雄, 佐治 英郎, 井上 修, 岡田 昌二, 鈴木 和年, 田中 彰, 安原 眞人, 三宅 義徳, 久下 裕司, 千田 道雄, 伊藤 正敏  核医学  38-  (2)  131  -137  2001/03/20  [Not refereed][Not invited]
  
• PET Summer Seminar Highlights 2001

  久下裕司, 塚本江利子, 中駄邦博, 久保直樹, 玉木長良  映像情報メディカル  33-  (12)  1204  -1210  2001  [Not refereed][Invited]
  
• 心筋脂肪酸代謝イメージング：123I-BMIPP SPECTと11C-palmitate PET

  森田浩一, 久下裕司, 加藤知恵次, 玉木長良  BME  15-  (8)  40  -44  2001  [Not refereed][Invited]
  
• Clinical roles of perfusion and metabolic imaging.

  Tamaki N, Kuge Y, Tsukamoto E  J Cardiol  37-  (Suppl I)  57  -64  2001  [Not refereed][Invited]
  
• The role of fatty acids in cardiac imaging

  N Tamaki, K Morita, Y Kuge, E Tsukamoto  JOURNAL OF NUCLEAR MEDICINE  41-  (9)  1525  -1534  2000/09  [Not refereed][Invited]
   

  Nuclear medicine has progressed in conjunction with the recent growth of molecular medicine. Myocardial energy metabolism has long been investigated in experimental models with the use of Langendorff's method or coronary sinus blood sampling. However. the introduction of a variety of radiopharmaceutical agents has now made possible easy visualization of myocardial energy metabolism in vivo with nuclear medicine techniques.
• 特集“新世紀における核医学の展望―FDG-PETの有用性と経済効果を中心に―” ?-2．使い捨てFDG合成キットの利点と医療経済効果

  久下裕司, 塚本江利子, 玉木長良  INNERVISION  15-  (12)  88  -93  2000  [Not refereed][Invited]
  
• 心臓核医学―治療効果判定のための核医学―

  玉木長良, 森田浩一, 久下裕司  呼吸と循環  48-  (10)  1055  -1059  2000  [Not refereed][Invited]
  
• ポジトロン断層撮影法（PET）の虚血性心疾患への応用

  玉木長良, 森田浩一, 久下裕司, 塚本江利子  循環器科  48-  (4)  331  -335  2000  [Not refereed][Invited]
  
• 特集“21世紀におけるPET画像の役割” 心臓

  玉木長良, 森田浩一, 久下裕司  臨床放射線  45-  1055  -1064  2000  [Not refereed][Invited]
  
• 心筋レセプターの核医学イメージング

  久下裕司  RADIOISOTOPES  49-  249  -251  2000  [Not refereed][Invited]
  
• 動物用PET−脳機能の研究：疾患モデルを用いて

  久下裕司  PET通信  25-  10  -12  1998  [Not refereed][Invited]
  
• 脳内の酵素活性の核医学イメージング

  久下裕司  RADIOISOTOPES  46-  697  -698  1997  [Not refereed][Invited]
  
• PETによる脳内AchEマッピング：アルツハイマー病診断の可能性

  久下裕司  ファルマシア  33-  57  -58  1997  [Not refereed][Invited]
  
• ラットのＰＥＴ

  久下裕司, 峰松一夫, 長谷川泰弘, 三宅可浩  循環器病研究の進歩  17-  85  -91  1996  [Not refereed][Invited]
  

Books etc

• 放射線技術学シリーズ：放射化学（改訂4版）

  久下裕司 (Contributor第8章 4. PETの化学/5.分子イメージング)
  オーム社 2023
• わかりやすい核医学 第2版

  久下裕司 (ContributorⅠ核医学で知っておくべき最低限の基礎知識 A放射能・放射線の基礎 B放射性医薬 pp2-16)
  文光堂、東京 2022
• 放射線技術学シリーズ：核医学検査技術学 第4版

  久下裕司 (Contributor第2章 放射性医薬品 pp.36-44)
  オーム社、東京 2022
• Radioimmunodetection of Atherosclerotic Lesions Focusing on the Accumulation Mechanism of Immunoglobulin G

  Shimizu Y, Hanzawa H, Zhao Y, Nishijima K, Fukura S, Sakamoto T, Zhao S, Tamaki N, Kuge Y (Joint workpp.141-150)
  Perspectives on Nuclear Medicine for Molecular Diagnosis and Integrated Therapy. (Kuge Y, Shiga T, Tamaki N, eds.), Springer 2016
• Discovery and Evaluation of Biomarkers for Atherosclerosis

  Sakamoto T, Hanzawa H, Manri N, Sakakibara M, Shimizu Y, Zhao Y, Zhao S, Yamada S, Kamiya K, Eki Y, Suzuki A, Higuchi H, Sugano C, Tsutsui H, Tamaki N, Kuge Y (Joint workpp.131-139)
  Perspectives on Nuclear Medicine for Molecular Diagnosis and Integrated Therapy. (Kuge Y, Shiga T, Tamaki N, eds.), Springer 2016
• Preclinical Evaluation of a Thymidine Phosphorylase Imaging Probe, [123I]IIMU, for Translational Research

  Nishijima K, Zhao S, Feng F, Shimizu Y, Akizawa H, Ohkura K, Tamaki N, Kuge Y (Joint workpp.125-130)
  Perspectives on Nuclear Medicine for Molecular Diagnosis and Integrated Therapy. (Kuge Y, Shiga T, Tamaki N, eds.), Springer 2016
• Development of a Microreactor for Synthesis of 18F-Labeled Positron Emission Tomography Probe

  Kuno N, Manri N, Abo N, Asano Y, Nishijima K, Tamaki N, Kuge Y (Joint workpp.113-124)
  Perspectives on Nuclear Medicine for Molecular Diagnosis and Integrated Therapy. (Kuge Y, Shiga T, Tamaki N, eds.), Springer 2016
• Semiconductor Detector-Based Scanners for Nuclear Medicine

  Takeuchi W, Suzuki A, Ueno Y, Shiga T, Hirata K, Okamoto S, Zhao S, Kuge Y, Kubo N, Kobayashi K, Watanabe S, Kobashi K, Umegaki K, Tamaki N (Joint workpp.51-65)
  Perspectives on Nuclear Medicine for Molecular Diagnosis and Integrated Therapy. (Kuge Y, Shiga T, Tamaki N, eds.), Springer 2016
• Perspectives on Nuclear Medicine for Molecular Diagnosis and Integrated Therapy

  Kuge Y, Shiga T, Tamaki N (Joint editor)
  Springer 2016
• 放射線技術学シリーズ：核医学検査技術学 第3版 第2章 放射性医薬品

  久下裕司 (Contributorpp.38-45)
  日本放射線技術学会 監修、大西秀雄・市原 隆・山本智朗 共編。オーム社 2016
• わかりやすい核医学 ?核医学で知っておくべき最低限の基礎知識 B放射性医薬品

  久下裕司 (Contributorpp.9-15)
  玉木長良、真鍋治編。文光堂 2016
• わかりやすい核医学 ?核医学で知っておくべき最低限の基礎知識 A放射能・放射線の基礎

  久下裕司 (Contributorpp.2-8)
  玉木長良、真鍋治編。文光堂 2016
• 放射線技術学シリーズ：放射化学 第3版 第8章 5.分子イメージング

  久下裕司 (Contributorpp.163-166)
  日本放射線技術学会 監修、東 静香、久保直樹 共編。オーム社 2015
• 放射線技術学シリーズ：放射化学第3版 第8章 4. PETの化学

  久下裕司 (Contributorpp.152-163)
  日本放射線技術学会 監修、東 静香、久保直樹 共編。オーム社 2015
• BRAND NEW 心臓核医学 E心臓核医学の展望。?循環器疾患および動脈硬化の分子イメージング

  久下裕司, 玉木長良 (Contributorpp.248-254)
  西村恒彦 編。金原出版 2012
• 新・心臓病診療プラクティス16 動脈硬化の内科治療に迫る 核医学検査

  玉木長良, 久下裕司 (Contributorpp.133-138)
  吉川純一、笠貫宏、土師一夫、別府慎太郎、松崎益徳 編。文光堂 2011
• ＮＥＷ 放射化学・放射薬品学 第９章 放射線と生体。9.1 身の回りの放射線とその生体への影響

  久下裕司, 関興一 (Contributorpp.209-213)
  佐治英郎 編。廣川書店 2011
• Non-invasive Optical Tracking of Bone Marrow Stromal Cells Transplanted into Rat Cerebral Infarct

  Sugiyama T, Kuroda S, Osanai T, Maruichi K, Chiba Y, Shichinohe H, Kuge Y, Tamaki N, Iwasaki Y (Joint workpp.139-144)
  Molecular imaging for integrated medical therapy and drug development. (Tamaki N, Kuge Y, eds), Springer 2010
• Bone Marrow Stromal Cell Transplantation for Central Nervous System Disorders ?Perspective for Translational Research and Clinical Application

  Kuroda S, Kuge Y, Tamaki N, Iwasaki Y (Joint workpp.126-138)
  Molecular imaging for integrated medical therapy and drug development. (Tamaki N, Kuge Y, eds), Springer 2010
• Molecular Imaging of Atherosclerotic Plaque Vulnerability: Comparison between 18F-FDG and 99mTc-Annexin A5

  Zhao Y, Kuge Y, Zhao S, Strauss HW, Blankenberg FG, Tamaki N (Joint workpp.69-77)
  Molecular imaging for integrated medical therapy and drug development. (Tamaki N, Kuge Y, eds), Springer 2010
• Initial Performance Measurement of an Integrated PET/SPECT/CT System for Small Animal Imaging

  Magota K, Kubo N, Narihiro K, Suzuki K, Nishijima K, Zhao S, Kuge Y, TamakiN (Joint workpp.60-68)
  Molecular imaging for integrated medical therapy and drug development. (Tamaki N, Kuge Y, eds), Springer 2010
• Molecular Imaging for the Assessment of Tumor Malignancy and Response to Therapy

  Kuge Y, Zhao S, Takei T, Tamaki N (Joint workpp.19-29)
  Molecular imaging for integrated medical therapy and drug development. (Tamaki N, Kuge Y, eds), Springer 2010
• Advances in Molecular Imaging

  Tamaki N, Kuge Y (Joint workpp.1-4)
  Molecular imaging for integrated medical therapy and drug development. (Tamaki N, Kuge Y, eds), Springer 2010
• Molecular imaging for integrated medical therapy and drug development

  Tamaki N, Kuge Y (Joint editor)
  Springer 2010
• 遺伝子医学MOOK, 創薬研究への分子イメージング応用 画像バイオマーカーとしての分子イメージングの利用 ７）治療効果評価への分子イメージングの利用 ?動脈硬化治療薬開発のための分子イメージング. 創薬研究への分子イメージング応用

  玉木長良, 趙芫, 久下裕司 (Contributorpp.201-205)
  佐治英郎 編。メディカル ドゥ 2010
• 遺伝子医学MOOK 別冊, 創薬技術の革新 マイクロドーズからPET分子イメージングへの新展開 PETが着目する課題3）循環器領域の分子イメージング

  玉木長良, 吉永恵一郎, 久下裕司 (Contributorpp.126-131)
  杉山雄一、山下伸二、栗原千絵子編。メディカル ドゥ 2010
• 心・血管病の分子イメージング 第1章 心・血管病の分子イメージングの歴史、現状

  玉木長良, 吉永恵一郎, 久下裕司 (Contributorpp.1-5)
  Jagat Narula監修、田原宣広編。永井書店 2010
• 臨床医とコメディカルのための最新クリニカルPET 第18章 心臓核医学の分子イメージング 1.心筋交感神経・受容体イメージング

  久下裕司, 西嶋剣一, 玉木長良 (Contributorpp.288-291)
  編集主幹：米倉義晴。先端医療技術研究所 2010
• IAEA RADIOISOTOPES AND RADIOPHARMACEUTICALS SERIES No. 1. Technetium-99m Radiopharmaceuticals: Status and Trends. Chapter 11 Technetium-99m Annexin-A5 for Apoptosis Imaging

  Kuge Y (Contributorpp.241-253)
  INTERNATIONAL ATOMIC ENERGY AGENCY 2009
• 放射線技術学シリーズ：放射化学 第2版 第8章4. PETの化学

  久下裕司 (Contributorpp.150-160)
  日本放射線技術学会 監修、花田博之 編。オーム社 2008
• 放射線技術学シリーズ：放射化学 第2版 第8章5. 分子イメージング

  久下裕司 (Contributorpp.160-163)
  日本放射線技術学会 監修、花田博之 編。オーム社 2008
• 放射線技術学シリーズ：核医学検査技術学 第2版 第2章 放射性医薬品

  久下裕司 (Contributorpp.36-42)
  日本放射線技術学会 監修、大西英雄･松本政典･増田一孝 共編。オーム社 2008
• 遺伝子医学MOOK9, ますます広がる分子イメージング技術 第2章 生物学的応用編 4. 心疾患の分子イメージング 2) 神経伝達・受容体機能解析

  玉木長良, 久下裕司 (Contributorpp.232-235)
  佐治英郎、田畑泰彦 編。メディカル ドゥ 2008
• 臨床医のためのクリニカルPET−病期・病態診断のためのガイドブック− 第I部 基礎・技術編 第1章 PET薬剤の最先端 1. PET薬剤開発の進歩

  久下裕司 (Contributorpp.11-14)
  伊藤正敏 編、先端医療技術研究所 2007
• An ultra-high-energy collimator for small animal imaging in dual-isotope study of 18F and 99mTc.

  Kubo N, Zhao S, Kinda A, Motomura N, Katoh C, Kuge Y, Tamaki N (Joint workpp.275-279)
  Positron Emission Tomography and Molecular Imaging: State of the Art and Future Perspectives, International Congress Series 1264 (Y. Kuge, N. Tamaki, eds), Elsevier Science B.V 2004
• Reduction of myocardial oxidative metabolism in dilated cardiomyopathy but not in remote areas in myocardial infarction.

  Noriyasu K, Tsukamoto T, Morita K, Kageyama H, Mabuchi M, Katoh C, Kuge Y, Kitabatake A, Tamaki N (Joint workpp.271-274)
  Positron Emission Tomography and Molecular Imaging: State of the Art and Future Perspectives, International Congress Series 1264 (Y. Kuge, N. Tamaki, eds), Elsevier Science B.V 2004
• In vitro and in vivo characterization of high specific activity S-(-) [11C]CGP-12177, a radioligand for β-adrenoceptors, in rats.

  Nishijima K, Kuge Y, Motoki N, Seki K, Ohkura K, Morita K, Tamaki N (Joint workpp.261-266)
  Positron Emission Tomography and Molecular Imaging: State of the Art and Future Perspectives, International Congress Series 1264 (Y. Kuge, N. Tamaki, eds), Elsevier Science B.V 2004
• The impact of coronary stenosis and risk factors on myocardial flow reserve.

  Tsukamoto T, Morita K, Noriyasu K, Katoh C, Kageyama H, Mabuchi K, Kuge Y, Nakada K, Okamoto H, Kitabatake A, Tamaki N (Joint workpp.257-260)
  Positron Emission Tomography and Molecular Imaging: State of the Art and Future Perspectives, International Congress Series 1264 (Y. Kuge, N. Tamaki, eds), Elsevier Science B.V 2004
• Time course of apoptotic tumor response following a single dose of chemotherapy: Detection with 99mTc-annexin V and comparison with blood flow, caspase-3 expression and TUNEL staining in an experimental tumor model.

  Takei T, Kuge Y, Zhao S, Mochizuki T, Strauss HW, Blankenberg F, Tait JF, Tamaki N (Joint workpp.249-252)
  Positron Emission Tomography and Molecular Imaging: State of the Art and Future Perspectives, International Congress Series 1264 (Y. Kuge, N. Tamaki, eds), Elsevier Science B.V 2004
• Methionine PET in differentiating recurrent brain tumor from radiation necrosis following cranial radiation.

  Katoh N, Nakada K, Takei N, Aoyama H, Shirato H, Kato C, Kuge Y, Tsukamoto E, Tamaki N (Joint workpp.217-221)
  Positron Emission Tomography and Molecular Imaging: State of the Art and Future Perspectives, International Congress Series 1264 (Y. Kuge, N. Tamaki, eds), Elsevier Science B.V 2004
• Neuronal cyclooxygenase-2 induction associated with spreading depression and focal brain ischemia in primates.

  Yokota C, Kuge Y, Hasegawa Y, Inoue H, Tagaya M, Abumiya T, Kito G, Tamaki N, Minematsu K (Joint workpp.191-196)
  Positron Emission Tomography and Molecular Imaging: State of the Art and Future Perspectives, International Congress Series 1264 (Y. Kuge, N. Tamaki, eds), Elsevier Science B.V 2004
• The loss of neuronal integrity may be one of the causes of cognitive disturbances in the patients with brain traumatic injury and normal FLAIR and T2-weighted MRI.

  Shiga T, Ikoma K, Tsukamoto M, Katoh C, Matsuyama T, Kuge Y, Nakada K, Tamaki N (Joint workpp.177-180)
  Positron Emission Tomography and Molecular Imaging: State of the Art and Future Perspectives, International Congress Series 1264 (Y. Kuge, N. Tamaki, eds), Elsevier Science B.V 2004
• Analysis of Neuronal and Glial Functions in Cerebral Ischemia: An Approach with Nuclear Medicine.

  Kuge Y, Kaji T, Hikosaka K, Yokota C, Seki K, Ohkura K, Shiga T, Minematsu K, Tamaki N (Joint workpp.44-52)
  Positron Emission Tomography and Molecular Imaging: State of the Art and Future Perspectives, International Congress Series 1264 (Y. Kuge, N. Tamaki, eds), Elsevier Science B.V 2004
• Clinical Nuclear Cardiology --State of the Art and Future Directions-- (3rd Edition) Section VIII Tracer Specific Imaging Technique, Chapter 35 Fatty Acid Imaging

  Tamaki N, Morita K, Kuge Y (Contributorpp.559-575)
  Elsevier 2004
• Positron Emission Tomography and Molecular Imaging: State of the Art and Future Perspectives

  Tamaki N, Kuge Y (Joint editor)
  International Congress Series 1264, Elsevier Science B.V 2004
• クリニカルPET 一望千里 第6章 実用編

  河嶋秀和, 久下裕司 (Contributorpp.179-199)
  西村恒彦、佐治英郎、飯田秀博編。メジカルレビュー社 2004
• Brain ischemia and spreading depression in a primate model.

  Yokota C, Kuge Y, Tagaya M, Hasegawa Y, Abumiya T, Kito G, Yamaguchi T, Minematsu K (Joint workpp.127-144)
  Strategic medical science against brain attack (Kikuchi H, ed.), Springer-Verlag 2002
• Annual Review 腎臓 ｢ポジトロン断層撮影法（PET）｣

  玉木長良, 塚本江利子, 久下裕司 (Contributorpp.55-58)
  伊藤克巳、浅野 泰、遠藤 仁、御手洗哲也、東原英二 編。中外医学社 2002
• 放射線技術学シリーズ：核医学検査技術学 第2章 放射性医薬品

  久下裕司 (Contributorpp.34-44)
  日本放射線技術学会 監修、大西英雄･松本政典･増田一孝 共編。オーム社 2002
• 循環器疾患---state of arts, ver.2 全面改訂版, 別冊・医学のあゆみ ｢診断法をめぐる最近の進歩, 虚血性心疾患, ポジトロン断層撮影法｣

  玉木長良, 久下裕司 (Contributorpp. 277-279)
  矢崎義雄、島田和幸、井上博、永井良三 編。医歯薬出版 2001 277-279
• 放射線技術学シリーズ：放射化学 第6章5. PETの化学

  久下裕司 (Contributorpp.143-154)
  日本放射線技術学会 監修、花田博之 編。オーム社 2001
• クリニカルPETハンドブック ｢心筋のバイアビリティ診断、心筋受容体の最近の知見｣

  玉木長良, 久下裕司 (Contributorpp.117-123)
  鳥塚莞爾、小西淳二、増田康治、西村恒彦、玉木長良、伊藤健吾、佐治英郎 編。技術経済研究所 2001
• Animal PET Study in Development of Novel PET Tracers.

  Kuge Y, Kawashima H, Ejima N, Miyake Y, Hashimoto N, Hashimoto T, Imanishi M, Shiomi M, Minematsu K, Hasegawa Y, Yamaguchi T, Tamaki N (Joint workpp.297-304)
  Positron Emission Tomography in the Millennium”, International Congress Series 1197 (Tamaki N, Tsukamoto E, Kuge Y, Katoh C, Morita K, eds.), Elsevier Science B.V. 2000
• Modified Method for Quantifying Regional Myocardial Blood Flow Using 15O-water with PET

  Katoh C, Kuge Y, Morita K, Tsukamoto E, Tamaki N, Knuuti J (Joint workpp. 273-278)
  Positron Emission Tomography in the Millennium”, International Congress Series 1197 (Tamaki N, Tsukamoto E, Kuge Y, Katoh C, Morita K, eds.), Elsevier Science B.V. 2000
• Visualization of Normal Organs in Whole-Body PET Imaging with F-18 FDG

  Kato T, Tsukamoto E, Suginami Y, Mabuchi M, Yoshinaga K, Takano A, Adachi I, Shiga T, Morita K, Katoh C, Kuge Y, Tamaki N (Joint workpp.221-224)
  Positron Emission Tomography in the Millennium”, International Congress Series 1197 (Tamaki N, Tsukamoto E, Kuge Y, Katoh C, Morita K, eds.), Elsevier Science B.V. 2000
• Clinical Usefulness of FDC-PET in the Patients with Differentiated Thyroid Cancer after Total Thyroidectomy

  Shiga T, Tsukamoto E, Kato T, Morita K, Adachi I, Mabuchi M, Yoshinaga K, Suginami Y, Takano A, Tamaki N, Katoh C, Kuge Y (Joint workpp. 181-185)
  Positron Emission Tomography in the Millennium”, International Congress Series 1197 (Tamaki N, Tsukamoto E, Kuge Y, Katoh C, Morita K, eds.), Elsevier Science B.V. 2000
• Quantitative Analysis for Myocardial Glucose Utilization Using Positron Emission Tomography and F-18-Deoxyglucose

  Morita K, Katoh C, Yoshinaga K, Adachi I, Shiga T, Mabuchi M, Itoh Y, Konno M, Kohya T, Kitabatake A, Kuge Y, Tsukamoto E, Tamaki N (Joint workpp. 141-145)
  Positron Emission Tomography in the Millennium”, International Congress Series 1197 (Tamaki N, Tsukamoto E, Kuge Y, Katoh C, Morita K, eds.), Elsevier Science B.V. 2000
• Clinical Utility of Combination of FDG-PET and CBF-SPECT in Extratemporal Lobe Epilepsy

  Takano A, Shiga T, Kobayashi J, Nakamura F, Adachi I, Katoh C, Kuge Y, Koyama T, Tsukamoto E, Tamaki N (Joint workpp. 73-78)
  Positron Emission Tomography in the Millennium”, International Congress Series 1197 (Tamaki N, Tsukamoto E, Kuge Y, Katoh C, Morita K, eds.), Elsevier Science B.V. 2000
• Positron Emission Tomography in the Millennium

  Tamaki N, Tsukamoto E, Kuge Y, Katoh C, Morita K (Joint editor)
  International Congress Series 1197, Elsevier Science B.V 2000

Association Memberships

• Japanese radioactive medicine science society   Japanese Society for Molecular Imaging   JAPANESE SOCIETY OF RADIATION SAFETY MANAGEMENT   The American Society of Nuclear Medicine   Cerebral Blood Flow and Metabolism   THE JAPANESE PHARMACOLOGICAL SOCIETY   THE PHARMACEUTICAL SOCIETY OF JAPAN   THE JAPANESE SOCIETY OF NUCLEAR MEDICINE   

Research Projects

• フェロトーシス誘導がん治療のPETイメージング

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

  Date (from‐to) : 2021/04 -2025/03 

  Author : 久下 裕司
• PETによるフェロトーシスイメージング：動脈硬化プラークの不安定性評価への挑戦

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory)

  Date (from‐to) : 2021/07 -2024/03 

  Author : 久下 裕司
• サイクロトロンで製造した68Gaを用いる前立腺がん診断用PET薬剤：68Ga-PSMAの標識合成法開発

  国立研究開発法人 日本医療研究開発機構：医療研究開発推進事業費補助金（橋渡し研究戦略的推進プログラム）シーズA支援費

  Date (from‐to) : 2018 -2018 

  Author : 久下裕司
• オン・デマンドPET検査のための新しいディスポ・チップ型PET薬剤合成装置

  文部科学省：科学研究費補助金(挑戦的研究（萌芽)）

  Date (from‐to) : 2017 -2018 

  Author : 久下 裕司
• 補体複合体のin vivoイメージングによる慢性炎症病態評価法の開発

  国立研究開発法人 日本医療研究開発機構：医療研究開発推進事業費補助金（橋渡し研究戦略的推進プログラム）シーズA支援費

  Date (from‐to) : 2017 -2017 

  Author : 久下裕司
• 動脈硬化の治療戦略に役立つ核医学イメージング法：EBMのための実験的研究

  文部科学省：科学研究費補助金(基盤研究(B))

  Date (from‐to) : 2014 -2017 

  Author : 久下 裕司
• 補体因子Properdinのin vivo可視化による不安定プラーク検出法の開発

  北海道臨床開発機構：医療研究開発推進事業費補助金（橋渡し研加速ネットワークプログラム）シーズAに係る研究開発委託費（シーズ育成経費）

  Date (from‐to) : 2016 -2016 

  Author : 久下裕司
• 動脈硬化症のRI治療への挑戦：マクロファージ浸潤抑制のためのRI内用療法剤の開発

  文部科学省：科学研究費補助金(挑戦的萌芽研究)

  Date (from‐to) : 2015 -2016 

  Author : 久下 裕司
• 新規放射線F-18ラベル法によるDNA取り込み型核酸代謝PET核医学診断薬の開発

  北海道臨床開発機構：医療研究開発推進事業費補助金（橋渡し研加速ネットワークプログラム）シーズAに係る研究開発委託費（シーズ育成経費）

  Date (from‐to) : 2015 -2015 

  Author : 久下裕司
• 慢性炎症の高精度イメージングを可能とする核医学診断材の開発

  科学技術振興機構：研究成果展開事業

  Date (from‐to) : 2014 -2015 

  Author : 久下裕司
• 不安定プラークの特異的イメージング：低分子人工抗体を用いた核医学診断薬の開発

  文部科学省：科学研究費補助金(挑戦的萌芽研究)

  Date (from‐to) : 2013 -2014 

  Author : 久下 裕司
• 不安定プラークの早期・特異的同定：プレターゲティング法による組織因子イメージング

  文部科学省：科学研究費補助金(挑戦的萌芽研究)

  Date (from‐to) : 2011 -2012 

  Author : 久下 裕司

   

  心筋梗塞や脳梗塞の根幹的原因である"動脈内のプラーク"の不安定性を精度よく評価できる診断法の開発が臨床画像診断学の急務である。本研究の目的は、プレターゲティング法を取り入れ、動脈内プラークの破綻とそれに伴う血栓形成に深く関与する組織因子(Tissue Factor, TF)の選択的な描出により不安定プラーク（粥状動脈硬化巣）を特異的に検出しうる新しい核医学イメージング法を提案することにある。この目的達成のため、今年度は以下の研究を実施した。１）anti-TF-mAb-SAv/18F-FBBのシステムの合成検討 18F標識ビオチン誘導体18F-FBBは、プレターゲティングユニットであるanti-TF-mAb-SAvと高い親和性を持つポストプローブであるが、18Fの半減期が約2時間であるため迅速な合成が必要である。この18F-FBBの標識前駆体である18F標識スクシンイミド誘導体18F-SFBの迅速合成のため、合成条件（温度、時間、溶媒等）を詳細に検討した。その結果、[18F]SFBの収量として4.7 ± 0.7 GBq（照射条件25 A, 20 min）、放射化学的収率として33.6 ± 9.5%（減衰補正なし）を達成した。合成時間は約55分程度、HPLCで求めた放射化学的純度は95%以上であり、迅速かつ高純度の[18F]SFBを得ることに成功した。２）モデル動物におけるPET撮像条件・TF発現の検討 TFイメージング実験の前段階として、大腿動脈バルーン障害ウサギを用いて、18F-FDGによるPET撮像実験と、病変部位におけるTF発現の検討を行った。PET撮像実験により200 MBq/rabbit程度の投与量で、動脈硬化病変を明瞭に描出できることが分かった。また、免疫染色により病変部における高いTF発現を認めた。
• 低酸素領域と血管新生因子のダブルターゲティング標識薬剤によるRI治療への挑戦

  文部科学省：科学研究費補助金(挑戦的萌芽研究)

  Date (from‐to) : 2009 -2010 

  Author : 成廣 賢史, 久下 裕司

   

  本研究は、腫瘍における低酸素領域とそれにともない発現する血管新生因子(チミジンボスホリラーゼ:TP)のダブルターゲットとするアイソトープ治療のためのI-131標識薬剤を合成し、その有効性と限界明らかにすることを目的とする。平成21年度において目的とする化合物(5I-6NIMUとI-AIMU)とその合成法を確立した。平成22年度は、その合成法を標識合成法へ応用すべく以下検討を行った。1.放射性ヨウ素標識体5-ヨード-6-ニトロイミダゾールメチルウラシル([^<125>I]5I-6NIMU)の合成6-ニトロイミダゾールメチルウラシルを[^<125>I]NISにより放射性ヨウ素標識化を行った。目的とする[^<125>I]5I-6NIMUの生成を高収率で確認できた。しかしながら単離精製後、溶媒留去の操作において放射化学的純度の低下(分解)が確認された。また、室温下1〜2時間の保存において放射化学的純度の低下を認めた。2.放射性ヨウ素標識体5-ヨード-6-アミノミダゾールメチルウラシル([^<125>I]I-AIMU)標品の合成経路と同様に、[^<125>I]5I-6NIMUをメタノール・アンモニア水中水素雰囲気下10%パラジウム炭素により還元反応を実施した。しかしながら[^<125>I]I-AIMUを得ることに成功していない。その原因として原料[^<125>I]5I-6NIMUおよび成績体[^<125>I]I-AIMUの不安定さが考えられた。5I-6NIMU及びI-AIMUの合成法に従い、放射性ヨウ素を用いた標識合成へ応用した。[^<125>I]5I-6NIMUの放射化学的純度は90%であったが、目的とする放射性ヨウ素化合物を得ることに成功し、アイソトープ治療のためのI-131標識薬剤への展開が示唆された。[^<125>I]I-AIMUを得ることに成功しておらず合成経路を再検討中である。
• Molecular imaging for dynamic analysis of cancer pathological states : Toward clinical molecular imaging

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))

  Date (from‐to) : 2008 -2010 

  Author : Yuji KUGE

   

  In the present study, we utilized molecular imaging technology that visualized tumor proliferation and hypoxia, and demonstrated the usefulness in the analyses of tumor pathological states and response to molecular-targeted/radiation therapies, in animal models and clinical settings. We also demonstrated, in animal models, potentials and safety profiles of our novel candidate compound for angiogenesis imaging. The present results could provide important evidences to develop novel diagnosis and treatment strategy taking advantages of molecular imaging technology that visualizes alteration in tumor pathological states at molecular/cellular levels.
• 脳機能再生機構の解析と分子イメージング~臨床画像診断の実現を目指して~

  文部科学省：科学研究費補助金(萌芽研究)

  Date (from‐to) : 2007 -2008 

  Author : 久下 裕司

   

  本研究の目的は、脳卒中及びアルツハイマー病を対象として、PET・SPECTといった分子イメージング法を分子生物学的手法と融合させることにより脳機能の再生過程を解析し、これらの過程の臨床診断に有用な画像診断法を探索・考案することにある。今年度は、充実した環境(Enriched environment ; EE)及び通常環境の異なる環境下で飼育したラットを用いて、神経機能回復の観点から重要と考えられる梗塞周辺部において、シナプス新生のマーカーであるsynaptophysin (SYP)の発現変化を測定した。また、中枢神経細胞膜上に特異的に発現する中枢性ベンゾジアゼピン受容体を標的とし、これに選択的に結合する[^<125>I]iomazenilを用いたin vitro autoradiographyを行い、環境刺激による神経再構築イメージングの可能性を検討した。その結果、SYP発現密度は、EE群ではST群に比べ、皮質と線条体の梗塞周辺部でともに有意に高く、環境刺激によって梗塞周辺部のシナプス新生が亢進し、これが神経機能の回復に寄与している可能性が示された。また、EE群ではST群に比べ、皮質梗塞周辺部における[^<125>I]iomazenil集積が有意に高く、中枢性ベンゾジアゼピン受容体を指標とする神経機能イメージングにより脳機能の再生過程を解析できる可能性が示された。以上の結果より、放射性iomazenilなどのプローブを用いた核医学的手法により、脳虚血障害後の環境刺激による神経機能の回復を定量的に評価できる可能性が示された。
• Molecular imaging and strategies for cancer treatment: A Study to achieve noninvasive in vivo pathological evaluation by molecular imaging

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))

  Date (from‐to) : 2005 -2007 

  Author : Yuji KUGE

   

  Using positron emission tomography, we attempted to developed molecular imaging strategies that enable in vivo imaging of molecular mechanisms and/or characteristics of tumors, in order to contribute to personalized therapy of cancer patients. The results in the present study can be summarized as follows:1. Studies on molecular-targeted therapyIn our animal model, ^<18>F-FLT (a marker of DNA synthesis) can early detect the antiproliferative effects of the molecular-targeting therapy with gefitinib before significant changes in the tumor size, indicating the potential of FLT-PET in early monitoring of tumor response to the molecular-targeting therapy.2. Studies on radiation therapyThe results in an animal model indicated that post-radiation therapy response may be predicted by the accumulation of ^<18>F-FDG before complicated change, such as inflammation following irradiation, occurs.3. Development of molecular imaging probes that target molecular mechanisms of tumors.(1) For developing a thymidine phosphorylase (TP)-expression-based molecular imaging probe, we synthesized novel C-11 and I-123 labeled uracil derivatives, which were designed on the basis of one of the potent TP-inhibitors. The compounds synthesized possessed similar inhibitory potentials to the mother compounds.(2) A radioiodinated celecoxib derivative, ^<125I>-IMTP was synthesized. Our results showed a high inhibitory potency and selectivity of IMTP for COX-2, indicating its potential as a SPECT tracer for imaging cyclooxygenase-2 expression. In addition, we succeed to synthesizing a radioiodinated lumiracoxib derivative with reduced nonspecific bindings.(3) [^<99m>Tc-labeled anti-MT1-MMP (membrane-type-1 MMP) antibody accumulated in the tumor in time-dependent manner, indicating the potential of the labeled antibody for the imaging agent of tumor malignancy. In addition, the pre-targeting strategy improved S/N ratios.
• マイクロリアクタによるポジトロンプローブの合成:チップ型自動合成装置の開発へ

  文部科学省：科学研究費補助金(萌芽研究)

  Date (from‐to) : 2006 -2006 

  Author : 久下 裕司

   

  本研究では、マイクロリアクタを用いる合成技術をポジトロンプローブ合成に応用することにより、簡便・迅速な標識合成法を確立し、チップ型自動合成装置開発の可能性を探ることを目的とし、以下の検討を行った。すなわち、反応系の制御に優れたマイクロリアクターを用いることで、PET用ドパミンD2受容体イメージング薬である[11C]ラクロプライドを短時間内に効率的に合成しうるか否かを検討した。マイクロリアクターには、Y字型チャネル構造のチップ(200um(W)×20um(D)×250mm(L))を用いた。原料としてデスメチルラクロプライド(2mg/800ul)と[11C]ヨウ化メチルの各DMSO溶液を用意し、これを2つの注入口からそれぞれ導入し、反応させた。チップの出口より採取した反応液をHPLCにて分析し、[11C]ラクロプライドの収率を算出した。また、原料の注入速度、反応温度と収率との関係を検討した。その結果、マイクロリアクターでの室温における収率は20secで11.7±4.3%、60secで14.5±2.3%であり、短時間での高収率、かつ良好な再現性を認めた。一方、60℃における収率は、20secで20.3±2.0%であり、加温による収率のさらなる上昇を認めた。以上の結果は、マイクロリアクターを用いた効率的な[11C]ラクロプライド合成を示すものであり、本システムを応用することで、今後放射性プローブを簡便に供給できる可能性が示された。
• 動脈硬化病態の解析と分子イメージング:プロスタグランジン合成酵素を標的として

  文部科学省：科学研究費補助金(萌芽研究)

  Date (from‐to) : 2004 -2005 

  Author : 久下 裕司

   

  本研究では、動脈硬化モデルにおいて放射性標識COX-2阻害薬の動態を解析し、分子生物学的評価結果と対比することにより、COX-2を標的とする動脈硬化病態診断の可能性を検証することを目的とし、本年度は以下の検討を行った。1.COX-2を標的とする放射性薬剤の開発に関する検討昨年度までに、選択的COX-2阻害薬であるCelecoxibのヨウ素置換体(IMTP)をデザイン・合成した。今年度は、IMTPの分子イメージング剤としての有用性をさらに検証するため、ラットを用いてインビボでの評価を行った。その結果、IMTPは速やかな血中クリアランスを示し、優れた標的/血液比を示した。これらの結果より、IMTPのCOX-2選択的イメージング剤としての可能性がインビボ実験において示された。2.動脈硬化モデルウサギにおけるCOX-2発現の検討動脈硬化病態、特に、プラーク破綻には、細胞外マトリックス分解酵素(MMP)が深く関与している。最近、MMPがプロスタグランジン(PG)E2依存性の経路により産生されることが示され、PGE2合成の律速酵素であるCOX、特に誘導型であるCOX-2の役割が注目されつつある。そこで、動脈硬化モデル家兎においてCOX-2発現を解析し、MMP-2の発現と対比することにより、COX-2を標的とする動脈硬化病態診断の有用性を検証した。その結果、MMP-2は、最も不安定性を示すアテローム性病変に強く発現していた。一方、COX-2は初期病変から進行性病変にわたって広く発現していた。これらの結果は、COX-2を標的とする分子イメージングにより動脈硬化病変の早期検出が可能であり、他方、MMP-2イメージングでは進行性病変の描出が可能であることを示唆している。
• Molecular imaging and patho-functional analysis of cerebral ischemia : focused on prostaglandin synthases

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))

  Date (from‐to) : 2002 -2004 

  Author : Yuji KUGE

   

  In order to clarify 1)the roles of cyclooxygenase-2(COX-2) in the pathophysiology of cerebral ischemia and 2)the potentials of COX-2 molecular imaging in the patho-functional analysis of the disease, we planed the present project using molecular imaging technique. Our findings in this project were as follows :1.Temporal changes of cerebral blood flow, metabolism, and neuro-receptor in animal models of cerebral ischemiaIn ischemic regions where neuro-receptor function was preserved, neuronal DNA is still intact and cellular integrity is maintained. COX-2 expression was often observed in these regions.2.Cyclooxygenase-2 expression in animal models of stroke(1)The time course of COX-2 mRNA expression in the ischemic core was different from that of the peri-infarct area. The expression of COX-2 in focal ischemic tissues is determined by the depth and duration of CBF reduction.(2)Upregulation of bilateral S-100A9 and ipsi-lateral IL-1β and IL-6 genes, induced by the Spreading Depression(SD) elicitation were demonstrated to be downregulated by a selective COX-2 inhibitor JTE-522.3.Development of molecular probes for imaging COX-2 expressionWe intended to develop a radioiodinated coxib as a SPECT tracer for imaging COX-2 expression and designed 5-(4-iodophenyl)-1-[4-(methylsulfonyl)phenyl]-3-(trifluoromethyl)-1H-pyrazole (IMTP). ^<125>I-IMTP was successfully synthesized with a high specific activity. Our results showed a high inhibitory potency and selectivity of IMTP for COX-2, indicating its potential as a SPECT tracer for imaging COX-2 expression.
• 核酸合成・PG合成酵素のインビボイメージング:腫瘍・炎症の鑑別診断への挑戦

  文部科学省：科学研究費補助金(萌芽研究)

  Date (from‐to) : 2002 -2003 

  Author : 久下 裕司

   

  腫瘍と炎症を精度良く鑑別し、治療方針の決定に役立てることが、診断医学の最重要課題の一つである。申請者らは、核酸合成及びプロスタグランジン合成酵素(COX)を標的とし、ポジトロン断層撮影法(PET)、シングルフォトン断層撮影法(SPECT)による腫瘍/炎症の鑑別診断能を向上させることを目的として本研究を計画した。この目的を達成するため、本年度は以下の検討を行った。(1)[C-11]ホスゲンを用いる核酸誘導体の簡便な標識合成法の開発研究数種の標識前駆物質を合成し、チミン、チミジンの非標識合成及びC-11標識合成を試みた。その結果、新規に合成された標識前駆物質により非標識チミンの合成に成功した。さらに、この標識前駆物質と[C-11]ホスゲンとの反応により[C-11]チミン、[C-11]チミジンの合成に成功した。(2)COX阻害薬の放射標識合成法の開発研究構造-活性相関学的検討から、選択的COX-2阻害薬であるCelecoxibのヨウ素置換体をデザインした。さらに、放射性ヨウ素標識体を得るため、数種の標識前駆物質の合成、及びヨウ素置換体の合成を試み、これらに成功した。(3)モデル動物に関する検討核酸合成及びプロスタグランジン合成酵素を標的とする腫瘍診断の有用性を評価するため、対照として糖代謝、アポトーシス、及び低酸素マーカーの腫瘍・炎症内分布をモデル動物において測定した。現在、上記(1)(2)に記載した標識化合物の腫瘍・炎症内分布を検討中である。
• 腫瘍/炎症内ブドウ糖代謝・膜輸送遺伝子と背景因子:腫瘍鑑別診断のための基礎的研究

  文部科学省：科学研究費補助金(奨励研究(A))

  Date (from‐to) : 2000 -2001 

  Author : 久下 裕司

   

  ^<18>F-FDGを用いるPET検査は、悪性腫瘍の鑑別診断、治療効果判定などにおいてきわめて有効性が高い。しかし、^<18>F-FDGは一部良性疾患にも集積することが明らかとなり、本検査による腫瘍鑑別診断の限界が指摘されている。これらの鑑別診断をより的確に行うには、悪性腫瘍や良性疾患への^<18>F-FDGの集積機序を明らかにすることが必須である。一方、最近、腫瘍・炎症へのFDG集積にはGlucose transporter(GLUT)が関与していることが明らかとなってきた。本研究では、腫瘍、感染性炎症、非特異的炎症モデルラットを用い、実験的腫瘍及び炎症組織におけるFDG集積とGLUT発現に及ぼすインシュリン及びグルコース負荷の影響を検討した。1.インシュリン負荷により腫瘍及び両炎症へのFDG集積は対照の約50%に低下したが、GLUT発現には大きな影響は与えなかった。2.グルコース負荷時のFDG集積は両炎症で対照の約50%、腫瘍で約85%であった。このとき、非特異的炎症ではGLUT1発現が有意に低下し、感染性炎症ではGLUT3発現が有意に低下した。GLUT1とGLUT3の発現は腫瘍では変化しなかった。したがって、グルコース負荷は腫瘍、炎症の鑑別診断の手がかりになる可能性がある。

Industrial Property Rights

• 特開2020-34493:放射性核種18Fの精製方法  2020/03/05

  久下 裕司, 阿保 憲史, 平田雄一  国立大学法人北海道大学
• 特開2020-33341:放射性フッ素標識化合物の製造方法及び放射性医薬組成物の製造方法  2020/03/05

  久下 裕司, 阿保 憲史, 桐生 真登  国立大学法人北海道大学，日本メジフィジックス株式会社
• 特開2019-156717:放射性医薬組成物の製造方法  2019/09/19

  桐生 真登, 中村 壮一, 久下 裕司, 阿保 憲史  日本メジフィジックス株式会社, 国立大学法人北海道大学
• 特許6472493:放射性医薬組成物の製造方法  2019/02/01

  桐生 真登, 外山 正人, 久下 裕司, 西嶋 剣一  日本メジフィジックス株式会社, 国立大学法人北海道大学
• 特許第6282436号:虚血性心疾患の評価方法、評価用キット及び評価装置  2018/02/02

  半澤 宏子, 坂本 健, 久下 裕司  株式会社日立製作所
• 特許第6226322号:放射性医薬組成物の製造方法  2017/10/20

  桐生 真登, 外山 正人, 久下 裕司, 西嶋 剣一  日本メジフィジックス株式会社, 国立大学法人北海道大学
• 特許第5417464号:動脈硬化病変を評価するための方法、キット、装置及び薬剤  2013/11/22

  久下 裕司, 坂本 健, 半澤 宏子, 万里 直己  株式会社日立製作所, 国立大学法人北海道大学
• 特許第5379616号:粥状硬化性動脈硬化のマーカー因子と用途  2013/10/04

  久下 裕司, 半澤 宏子, 坂本 健, 万里 直己  株式会社日立製作所
• 特許第5337096号:動脈硬化の評価法  2013/08/09

  久下 裕司, 半澤 宏子, 坂本 健, 万里 直己  株式会社日立製作所
• 特許第5311739号:放射性ラベル基を有する3−[3−(ベンゾイルアミド)ベンジルオキシ]アスパラギン酸誘導体とその製造方法  2013/07/12

  島本 啓子, 佐治 英郎, 久下 裕司, 上田 真史, 佐藤 公道, 中川 貴之  サントリーホールディングス株式会社
• 特許第5291791号:[18F]SFBの合成方法  2013/06/14

  中西 博昭, 齊木 秀和, 佐治 英郎, 木村 寛之, 河嶋 秀和, 戸松 賢治, 久下 裕司  株式会社島津製作所, 国立大学法人京都大学
• 特許第5208328号:放射性フッ素標識化合物  2013/03/01

  中田 徳仁, 奥村 侑紀, 桐生 真登, 永田 絵理子, 松本 博樹, 久下 裕司, 趙 松吉, 西嶋 剣一  日本メジフィジックス株式会社, 国立大学法人北海道大学
• 特許第5179811号:ウラシル化合物又はその塩、これらを有効成分として含有するイメージング剤、およびこれらを有効成分として含有する腫瘍診断をするためのイメージング剤  2013/01/18

  大倉 一枝, 関 興一, 西嶋 剣一, 高橋 正幸, 久下 裕司, 玉木 長良, 趙 松吉  学校法人東日本学園・北海道医療大学, 国立大学法人北海道大学
• 特許第5066599号:動脈硬化病変を評価するための方法及びキット  2012/08/17

  久下 裕司, 坂本 健, 半澤 宏子, 万里 直己  株式会社日立製作所, 国立大学法人北海道大学
• 特許第4528196号:ピリミジン誘導体の製造方法  2010/06/11

  大倉 一枝, 関 興一, 佐ノ木 公人, 西嶋 剣一, 久下 裕司, 玉木 長良  独立行政法人科学技術振興機構